I'll do this out of any real order, because these write-ups contain enough guesswork to embarass me already, even before I try to do a ranking.
LPR: Contenders
Danilo DiLuca is a proud guy, and undoubtedly chose this LPR team on a condition that it be constructed around his ambitions to defend his Giro title. I don't know a lot of the names, but Pietropolli and Bosisio are very competent all-rounders. Pietropolli and Savoldelli can help LPR survive the TTT with DiLuca's standing intact (remember, Liquigas launched his bid with a TTT win last year). Spezialetti was one of Il Killer's lieutenants last year. If all that fails, or even if it doesn't, look for one (last?) ripping Savoldelli descent off the Mortirolo in stage 20.
Astana: Contenders
As well known as they come. In fact, not only do we know that they're a GC team, we know exactly how they plan to win it: by forming a train in front of their GC guy(s) on the mountain stages and driving up the pace on all the climbs before the finale. Bruyneel has little history of chasing stage wins or lesser jerseys if it in any way detracts from the pursuit of the yellow -- er, maglia rosa. The only question is whether Contador is ready to launch a winning bid, or if the leadership could fall to Klöden. And one other question: how will they handle the pressure of an early lead? The old Postal train didn't have to worry much during the flat transitional stages in France, but the undulating, unpredictable first two weeks could be a nightmare for Bruyneel here.
Caisse d'Epargne: Contenders
Can José Rujano stay in contact during the TTT? Can they drag him up to the front of what will seem like a thousand classics-style bumpy stages with little uphill finishes and little time gaps here and there before the mountains? This is a great team: Arroyo, Karpets, J-Rod, Frankie Pérez, Pablo Lastras, Horrach -- probably my favorite team here -- and if Rujano can't ride the first two weeks efficiently enough to take advantage of his climbing, Unzue can turn to the best-placed of his half-dozen studs for results. Rodriguez especially looks like an ideal rider for some of the smaller end-of-stage climbs in the first two weeks. I hope they come out aggressively, this is going to be such a cool team to watch.
CSF: Contenders
Probably the best of the Italian non-PT teams aside perhaps from Simoni's outfit (yep, I didn't forget LPR). Sella has a shot at a podium place. Baliani is a cagey all-rounder who might be after the mountains jersey he just missed last year... if teammate Julio Pérez Cuapio doesn't nab it. These guys should be able to help Sella if he makes it to the Dolomites in position. Max Richeze is a top stage-hunter. But a complete meltdown in the TTT can't be ruled out.
FdJ: Stage hunters
Um... Veikkanen is going well, so he may enliven a stage or three. Le Boulanger has some climbing history... but not that much. After that, le deluge.
High Road: Semi-Contenders
Terrific roster of guys who can be counted on for various tasks: sprints, lead-outs, stage attacks, and a solid TTT. I just don't know if Possoni or Siutsou can get in position for a real GC run in the final week. Don't rule it out... or count on it.
Rabobank: Semi-Contenders
With two grand tour wins Denis Menchov should probably get a little more respect here, but as I've said before, his form and ambitions for the Giro are unclear to me. Ardila has a chance at a high GC placing, and if things are going well for one or the other, Rabo could have some real fun. I'd rate either of them above High Road's guys, but still a notch below the top GC teams.
Liquigas: Contenders
Maybe I should switch to a numerical scale or something... Leakygas are also a step below Astana, but definitely one above Rabo. Pellizotti has a little more background at the Giro than, say, Menchov, not to mention crystal-clear ambitions. With help from Noè and Nibali and Carlström, they'll be heard from in the final week for sure. But I'd bet more on a podium and a Ciclamena (points) jersey than the Maglia rosa.
Serramenti: Contenders
It's all about Gibo Simoni here. He's built himself quite a Swiss Guard of B-list climbers: Bertolini, Illiano, etc., while also adding some stage hunters in Hondo and Nardello. Nobody's plan is clearer: keep the old man safe and sound for two weeks, then see what happens.
Slipstream: Stage Hunters
On one hand, they clearly don't have anyone to challenge for the win. [Every time I say that, they challenge for a win.] But they will definitely be looking to make an impression. I like that they ride with that chip on their shoulder, wanting to make a name for themselves in Europe right now. Obvious contenders in the TTT and Zabriskie could easily bag two time trials.
Milram: Stage Hunters
I so want to label them "tourists," but Zabel and Astarloa are worthy of a little more respect than that.
Tinkoff: Stage Hunters
Three pretty good ones at that in Loddo (sprints), Petrov (climbs) and Ignatiev (bumpy stages). Last year they were in every breakaway... which is good for business.
CSC: Stage Hunters
Unless Sørensen is the new Andy Schleck, the overall won't be very realistic. A year after blowing their entire Giro in the TTT, CSC seem ready to make amends with a solid group of chronomen. Unfortunately, last year's TTT meant a lot more than this year's will. Larson, McGee, Voigt and O'Grady will all have a shot at stage wins though.
*Lotto: Tourists
OK, McEwen will be in on some sprints, but there won't be many of them, and he'll be hard-pressed to stay in contact beforehand. Matt Lloyd will show up someplace. That's about it.
Saunier Duval: Contenders
Nobody likes Riccardo Riccò these days, it seems, but until he blows up he's a top-shelf threat to win. This is a veteran GC team: Cañada, Camaño, Pagliarini and climber/stage-hunter deluxe Leo Piepoli. But after being completely invisible this year, you have to wonder whether this is any sort of a cohesive unit?
Quick Step: Stage Hunters
Bettini is il Capitano if he's fit enough to warrant any support. Alex Efimkin will follow the climbers around. Gárate might bag a stage earlier. But the guy the fans will be watching is wunder-ragazzo Giovanni Visconti. It's hard to be anonymous in the tricolore national champion's kit. There are a few stages he could bag.
Lampre: Semi-Contenders
Bruseghin, Bossoni, Spilak... surely someone will rescue their GC ambitions here? I'm pretty suspect of their chances for the overall, but you can bet someone on their roster will be hanging around.
Gerolsteiner: Stage Hunters
Förster, Oscar Gatto, Rebellin... they'll have their shots on occasion. Not a whiff of GC contenderness though.
Cofidis: Tourists
Stop me before I bag on a French team again. I guess I should be kind and repeat my Euskaltel assessment here.
Euskaltel: Tourists
I don't blame them for going through the motions this month. They pay their bills at the Tour and the Vuelta, and this is the best prep they can get.
AG2R: Stage Hunters
I have to say something nice about a French team, and Bweeg isn't here, so here goes. Valjavec is a Giro rider, but not quite on the highest slopes, so this isn't a great percorso for him. But he, Nocentini and maybe the eastern bloc guys will make an impression someplace. More than the other French teams, they look like they're here to do more than Tour prep.
Barloworld Contenders
A very curious team... Soler says he's a stage hunter, but nobody in their right mind should believe him, lest he bag a stage and a five-minute gap in the process. I've mentioned Pfannberger as someone to watch, and Geraint Thomas is another stage contender. Pretty solid squad all the way around. Barloworld just re-upped their sponsorship for another year, and the team might/should be well motivated to pay them back.