they're good, until you try a better one, I bought a canon 350d and thought it was ok, then bought a 40d and it was sooooo much better, if you ever upgrade you'll realise how bad your last one was
d90's are supposed to be ok, if I was you though, I'd save up and get a d300/d300s!! or even go for the equally as capable d200, would be worth the extra pennies