Going on the TV that I love.
Lost is a given.
I saw S1 and S2 on CH4 way back. Recently watched S1-4 straight through. Now i'm waiting for S1-6 boxset on BR. When this turns up (1 year maybe) i'll watch the whole lot again. There's enough going on in the series to easily justify repeated viewings (assuming you're a fan).
I love ER (especially the older stuff) and can watch various seasons repeatedly.
Although I was sceptical at first, i'd say 24 too. How can you not watch more than once, possibly the finest TV drama (S1/2 I'm referring too) ever

. Once again, waiting for a mammoth BR set and i'll start again from the beginning.
Heroes Season 1. Simply fantastic opening season (shame about the rest).
BSG. Awesome. Seen up to S4 part 1 and can't wait to watch the whole lot again once I pick up the BR set in the Black Friday/Xmas sales.
Lastly, House. Seen S1-3 a few times here and there. The BR set's of these are long overdue (come on Fox sort it out

).
In summary, I look forward to watching massive of great TV on BR box set's in 2010