hmm, basically TT's wouldn't last very long. New forks have really high prices relative to second hand items at that price. I would definately not recommend you buy new forks in that price range when there are plenty of other (and i mean loads) nicer forks, second hand, for the same money.
Just try to keep the travel down (e.g. not 120mm) as it will bump up the price, its not needed and it'll affect control.
Personally, i think the rockshox 'feel' (firm rebound and sag) is great for street, however, I've found they dont hold up to abuse as well as say, marzocchi's.
Hope I've helped. :S
Tom