Another vote for the 16-45, as you can get one used for less than $250. On top of that, it's a great lens, to boot.
Whether you prefer to shoot with zooms or primes is a highly personal thing. I like to have a combination of both around so I can pick and choose based on what I want to shoot and how much I want to carry.
From what you said in your OP, I'm assuming that you're new to DSLRs, so in addition to a wider angle zoom, I would also recommend picking up an inexpensive longer zoom. Depending on how tele you want to go, there are a couple of good choices that can be had for under $150, used: the DA50-200 or the Tamron 70-300. Shoot with the 2 zooms for a while so you can figure out which focal lengths you use the most; once you've figured that out, then you'll have a better idea of how you want to build your kit, whether it be upgrading your zooms or adding some primes, or a combination of both.
HTH,
Heather