The Lost season finale was definitely worth it. Even in the first 30 minutes it was MUCH improved over last season's anti-climactic finaly, and they had a good mix of revelations while still progressing things AND setting up a couple (maybe three even?) great cliffhangers for next season. I already can't wait, and it's not until SEPTEMBER. In the meantime, you can brush up on all the little crazy details, secrets, revelations, etc, at the VERY awesome Lostpedia. (Warning: If you haven't seen any of this season's episodes -- the site is VERY spoiler-heavy). You can also fill up the off-season following the Lost Experience ARG (alternate reality game).
Speaking of nothing to do until September, Lost was the pretty much the last of them -- all our shows are now over for the season. Doctor Who still has a few episodes, and I think The Sopranos and Big Love might as well, but all the standard network fare is over. I guess we'll have a lot less TV to watch and a lot more time to play with and stare at Evie instead. I'm also keeping my eye out for good off-season shows - for example, season 3 of The 4400 starts up in a couple weeks -- so if you see anything else good, let me know.