These days I buy almost exclusively trades. I basically only buy single issue comics if I think they won't ever come out as trades, either because they're one-shot deals or because they're unpopular. I'd much rather buy the trade, sit down for an hour, and read a complete story arc all at once. It's just nicer to read that way than spending 10-15 minutes once a month reading tiny installments. Plus trades are nicer to own, easier to store, they're more durable, they don't have ads crammed onto on every third page, and they often come with extras like concept art or rough draft scripts.
I'm house-sitting at the moment, so I don't have my comics/graphic novels/TPBs/THBs in front of me. But from memory, I have (excluding manga):
- Fables (Volumes 1-7)
- The Walking Dead (Volumes 1-4)
- Nightcrawler: The Devil Inside
- Origin
- Marvel 1602
- The Maxx (all except the last volume)
- Watchmen
- V for Vendetta
- Creature Tech
- The Dream Hunters
- Elektra and Wolverine: The Redeemer
- Owly (Volumes 1-3)
- Sandman: Taller Tales
- Arrowsmith (volume 1)
- Johnny the Homicidal Maniac
- Squee!
- Black Orchid
- Midnight Days
- The Books of Magic (volume 1)
- Powerless
- The Last Temptation
- A Circle of Cats
- Preacher (full series)
Plus whatever I'm forgetting, and some assorted comic adaptations of things like Terry Pratchett and R.A. Salvatore novels.
Jam it back in, in the dark.