I've talked about some of my quirks as a collector. I take special notice of "cameo players" who appear on another player's card, I don't mind (and often enjoy) vintage cards that are in poor shape, and every couple of years I get bored and reorganize my cards: by team, by year and brand, or even alphabetically by player. But one of my biggest interests in the hobby is accruing cards of each player in all of the different uniforms he's worn (or as many as possible). It's an entertaining way to visually catalogue a player's career. In the case of Robin Roberts, so far I only have him with the Orioles and the Phillies but not the Astros. Still, I can say that I've got multiple cards of a Hall of Fame pitcher, and that's pretty good.
When I open a pack of cards, the major thing that holds my attention (besides scanning for Orioles or especially unique photos) is whether I've gotten any players on a new team. I finally picked up a few jumbo packs of 2009 Topps Series 2 last Sunday, and they were pretty productive on that front: Edgar Renteria in Giants colors, Trevor Hoffman as a Brewer, John Smoltz with the Red Sox. I have to do some significant compilation of want lists; non-Topps Orioles are a priority. But it might be a good side project to check my card inventory (I put together an Excel database with all 26,000 or so cards in my collection) and figure out which player-team combos I need to make things a little more complete in my own eyes. There's still a fairly big gap from 1996 through the middle of this decade, when I was largely out of the hobby. Heck, at some point I might be sufficiently bored to rearrange my cards by player name and thereby to refill my binders with my various player movement tableaus.
Now that I reread that last sentence...I sure hope I'm never that bored.