Comments on the main page isn't a good idea. If you have a lot of comments, even if you have an expand/collapse feature and pagination, it gets cumbersome very quickly because people have to expand, read comments, then collapse and move down to the next post, etc. It becomes especially problematic if you get lots of comments. A couple blogs I visit frequently get 350 to 1000 comments on the first day of a post.
I've played with some themes with expand/collapse comments on the main page, and in my experience they only work if you seldom get over 10 comments on a post. If you have 20 or 50 on a post, the delay after clicking expand till the comments show is sort of irritating.