Almost all of this is solid. One small quibble:

"Black tie" means tuxedo. If your host doesn't really mean black tie, that's their mistake, not yours. Don't get a black suit. Everything a black suit can do, a charcoal suit does better.

I only bring this up because people seem to think black suits are essential. They aren't. You won't get funny looks, but you won't look as good as you would in charcoal.

BONUS TIP: Match your socks to your pants, not your shoes. You want to draw attention to the shoes/leg boundary, not the sock/trouser boundary.

BONUS LINK: http://www.styleforum.net is where I learned what I wanted to know about tailored men's clothing. Scour the stickies; dip into the daily threadpiles only with caution.