michael, set yourself a budget and buy the best you can within that price range. we've spoken to a number of people who've bought ones from aldi and whilst we know they're not as good as the named ones, they do a perfectly reasonable job.
we find we use the hide clamp far more than the tripod, it depends where you're going to use the scope the most. we bought ours from the rspb, can't remember which one it was, but the whole package (tripod, clamp, cover, scope and eyepiece) came to something under £400. we'd set ourself a budget of £500.
i agree with redman, about those with the biggest or fanciest scopes, you can often see people (usually men) eyeing up each others scopes in a hide, and they're the ones who'll not think twice about shoving you out of the way to get their fancy gear set up. they're generally the people who would never share a view too. we always let those without a scope have a look through it if there's something worth seeing.