Since I'm lurking, and others might find this useful, I'll point out some other things.
First, pulling in WP directly means loading a lot of code. It pulls in the entire WP engine, plugins, etc., which you might not want. Then again, you might want it (as it could give you spam blocking, referral tracking, etc. So, guess this has its pluses and minuses.
Second, without a caching engine behind the scenes, WP is dynamically regenerating the content. 2.0 has some optimizations for some of this, but otherwise where it's a custom query I'm not sure how it might be cached.
Third, last I looked at the WP query code, it was always retrieving EVERY field of the post(s) in question. That means even if you just want to show the excerpt, it still retrieves the ENTIRE post body from SQL as well. This is huge overhead (that I've eliminated through hacking the core code on my site, but I'd like to see this optimization done for real... ;)).
Lastly, an approach I/we sometimes lean towards is using something like CG-FeedRead (or other aggregator) to pull your own RSS feed from WP, insert it into your home-page, but then because CG-FeedRead caches to disk and only re-updates every N hours (AND as WP-Cache can be installed, which would also cache the feed on WP's end), your page would load VERY fast, but still be reasonably up-to-date (i.e., set the re-grab interval to 60 minutes, and you'll always be up-to-date within an hour at most).