The first choice is what what type of camera you want. It used to be that a DSLR was your only option for the flexibility of interchangeable lenses. That is no longer the case, as there is a growing crop of "mirrorless" cameras with these features.

We've got a number of questions covering this from several different angles, and I've chosen a number of them which I think make good starting reading:

• Is gallery quality possible with a mirrorless camera?
• Are mirror-less cameras good enough to buy instead of a DSLR for home/amateur use?
• How do Micro 4/3s cameras compare with DSLR cameras?

This is particularly relevant because the more-compact and more discreet mirrorless cameras are often especially appealing for street photography.

You might also want to give a bit of consideration to cameras like the Canon G1 X or Sony DSC RX100, which have a larger sensor and a decent, non-interchangeable lens. These may fit your needs at considerably less than your price point.

I don't think we have a really good question about narrowing down brands of mirrorless cameras, but if you've decided that you really do want a DSLR — and that's not a bad choice! — we have some great answers comparing brands in a relatively unbiased, non-partisan way:

• Is there any significant difference between Nikon and Canon?

and don't forget

• What do Pentax and Sigma DSLRs offer that differs from Canon and Nikon?

because the "next tier" brands offer some unique advantages that might fit your needs and style.

And related to all that, if you do choose a camera with interchangeable lenses, it's valuable to center your decision around that, as different systems will give you different options. See:

• How much do lens lineups vary across DSLR platforms?

for some great stuff on that. Traditionally for street photography, a 35mm equivalent focal length (around 24mm on a non-full-frame DSLR) is common, or else 50mm equivalent. If you're really focusing on portraits, you might want something a little longer, but that depends on your style. From your description of how you're planning to work, I'd strongly consider that you think about finding one prime lens that you really love — don't worry about covering all the options. (Reading: A great blog post from photographer Kirk Tuck on that topic, and one from Mike Johnston on prime lenses and also a few from Mike's site on the less-extreme idea of a two-lens kit.)

I know that's a lot to read and not nearly as simple as a "buy this; it's in your price range" recommendation (if you really want that, I'll point you back to Mike Johnston and his tongue-in-cheek-but serious Letter to George), but I think the links above will be really helpful and make you better equipped to make your decision.