There is an excellent thread at Cre8asite Forums named $2000 For a Search Engine Thrill Ride and Low Conversions? It discusses where people should put a $2,000 Web site budget towards.
Honestly, this is a hard one to sum up and the thread is not too long. If you have 2k to spend, not more, then check out the thread for some good ideas.
Forum discussion at Cre8asite Forums.