1000+ khash is reasonable, yes. I get 700 khash on my 7-year old desktop, and 1000 khash per core on my 3-year old laptop. The laptop's GPU gets 2000 khash. But yeah, the best thing you could do right now, if you really want to make a few cents, is to join a mining pool. Google for the "Bitcoin difficulty calculator" to see that it would most likely take over a year at the current difficulty before your 1000 khash/s would generate a block.
Only reason I'm still mining with my pitiful 700 khash/s is because I've got nothing better to do with the computer, I'm in a college apartment so electricity is free (more or less), and it earns me 0.20 BTC every week or so, which is better than nothing.