I regret buying basically anything not SW and animated Batman/Superman figures.
-The first four McFarlane monsters (Dracula, Frankenstein, Hunchback, Wolfman). Cool looking but lost interest quick. A dozen+ Spawn figures. After the detail's ooohhh factor wore off, they were just brittle toys of characters I knew little about.
-Everything ToyBiz, especially the female characters when it was the fun thing to chase down. It didn't matter how crappy they looked, the hunt was on.
-Three figures from Trendmasters Tarzen line. What the heck was I thinking?
- A couple of figures from "Congo".
-Four Aliens and Predator figs. Just got caught up in the collecting craze.
-The larger ship from Titan AE just to get the figure for customizing. Thankfully I got it on clearance for $10.
-About 4 basketball players from the old Kenner sports figures line (can't remember what it's called). Yeah, as if the Warriors' 1st round pick, Joe Smith, would have an impact in Oakland.

Jason Kidd was an alright decision because of his Bay Area connection. All in all, the figures suck because of the generic bodies and crap-lame detail.
-Dozens of of Star Trek. It just got out of hand and I was buying just to buy instead of restricting myself to only the figures I truly wanted.
-And yes, LEGO. I jumped into that feet first -- SW, trains, archeology adventure sets, witch castle, lots of packs of mini-figs, even picked up a couple of smaller older pirate sets. A month later, I was sick of it all.