Here are the comic series that I currently wait for the trade to get & read:
Ultimate Fantastic Four
Y, the Last Man
The Walking Dead
various mini-series from Marvel & Oni
Usually I'm waiting for the trade either because I didn't start reading it in floppies, and once I've started with trades that's the best way to continue; or because I used to read it in floppies but I feel that it reads better as larger chunks.
How about you--what do you prefer to read in trades as opposed to floppies?