Canon and Nikon are the best, Canon being slightly superior.
I'd recommend a used Canon 30D (~$450, I have one and it's great!), the Canon 18-55 IS kit lens (~$100 used, I've seen people taking amazing pictures with this thing on POTN, make sure to check out the lens sample archives!) and lastly the Canon 55-250 IS lens (~200 used, I see it recommended quite often over at POTN, check lens sample archives again..) and a 430EX flash will run you ~$235. You'll likely move away from those lenses at some point, but I think that set-up will serve you well. Good luck!