Best fonts for formal personal letters...?

That’s my favorite, because it looks handsome but *not as * professional as Times, etc.

Unless you’ve got mad typography skillz, don’t mix two serif or sans-serif faces in the same document. If you use Georgia for the address, and Times for the body text, it looks like you ran out of one or the other. The effect can be subtle, but anyone who knows type will be laughing at you.

That paragraph looks a bit odd? It should, since I mixed Georgia and Times in it.

Mixing a serif and sans-serif face is just fine. There are countless books that have been set using something like Times for the text and Arial for section headers. Throw in Courier for things like computer commands or responses, and 99% of the time, you’ll find that you only really need two faces, plus that odd bit of computer-ese:

Data Entry
After entering your name and address, the computer should respond with Enter phone number >