a good blank template for embedding in a website

Does anybody have a suggestion for a GOOD blank (or very simple) template for embedding a blog in to an existing website. I’ve tried a couple of times now and keep running into problems. Perhaps I need to make my own completely from scratch, but I’d rather not.

1) What files do I really need?
I last used “Naked” theme because it had the least files in it, only to find that since it didn’t have a file for the search box that I couldn’t easily fix problems I was having. Other blank templates I tried had many more files but were they all necessary? If I did make my own from scratch, could I still use widgets?

2) Are there any blank themes which won’t clash with my existing website CSS?
So far the answer to that has been no, as all templates I’ve tried have had CSS for generic things like h2, div, p, etc., which totally messed up my site template because I already had those tags designated. It would be great to have a template where everything were specifically named CSS tags (like div class = custom name) so that it won’t clash with my existing code? So far this has been the biggest problem as I spend all my time “fixing” these conflicts.

3) Perfect world would be a template where you just insert the include call to your existing header file and footer file and the blog just worked seamlessly inside it. Anything out there like that?