The Where In the World Is Matt Lauer game is my recent favorite. It's only 20 tickets vs. Flexicon's 25 per game, but it's just 4 multiple choice questions. Most are very easy, so the points accumulate faster than in any other game for me (and with less clicking).
I'm up to ~28,400 tickets and and debating between accumulating 35k+ in case 360s restock or taking a Zune or Vista. I'm primarily a Mac user (making a Zune less valuable), already have XP on my Mac, and have no 360 (yet) to make Rock Band worthwhile, so I've been unmotivated to play lately...
I know Vista also had a price drop at retail over the winter, so I keep hoping for a drop on LSC, too.
-Eric