insurance, tires, parts (clutch, brakes, this, that), finding competent mechanic (it takes a few), tickets?, haters screwing w/ your car when it's parked at the movie theater, mods, rebuilds, lots of gas...
if you're young, multiply everything by 1.5 b/c you won't have the restraint to keep your costs down (i was 23 w/ a brand new 98, i know..)
if you do your own work, it's more reasonable... if you go BPU, it's a lot less reasonable...
i've bought my car new in 98 for about $48k... in the past 5 years, i've probably averaged $5-10k/year including a rebuild over the past 3 months.