I'm looking forward to finally be able to raid 10-mans only, and still get competitive gear. 10-mans allow me to play with a few good friends, have fun on Ventrilo, look at the scenery and overall enjoy the raids and encounters a lot more than when catherding in 25-mans. 25-mans in WotLK are fun in their own way, but I find it to be too much hassle to get 24 other decent and dedicated people together, there's always a problem at some point. It's also easier for us "Serious about raiding, but can't raid 6 days a week"-people to gear up, as we don't have to farm emblems and gear from both 10 and 25-man to feel like we are doing everything we can to get the best possible gear.
In addition, the new raidlockouts with being saved to bosses and not a single raid-ID is genius, and will allow me to use my alts for my mains raid when needed and then later go finish up the last bosses on my alt with another group. Great kudos to Blizzard for giving me hope that raiding in Cata will be even more fun than WotLk!