Best way to burn I-Tunes/Mac

I have a G-4 Mac with I-Tunes, dial-up, external cd burner.
What is the best settings for:

MP3 or AIFF?? ( or another setting?)

Streaming Buffer:
what size? Small, Medium, or large?
Whenever I try to download the 30 second preview of a song it loses the stream about every four seconds.

Preferred speed?

Disc Format:
Audio or MP3?

Thank you in advance if anyone has any experience with the Mac and burning cd's.
IMPORT: There's a trade-off between file size and quality. AIFF (and WAV) are CD-quality, but a full CD will chew up 700-800MB of hard drive space. MP3 (or AAC, if you have the newer versions) are compressed, so they can take up as little as a tenth of that space. I suggest you try MP3s of various resolutions to see what you can live with, sound-wise.

STREAMING: Can't help you on this one.

BURN SPEED: I usually do it at maximum speed, and I've only burned the occasional coaster. I haven't done enough experimenting at slower speeds yet to know whether that would solve the problem.

FORMAT: Besides sound quality (see above), there's the issue of, what will my other equipment play? Few CD players will play MP3 disks, but many DVD players accept them.
I import AAC iles from the iTunes site. I inport music from CDs usng AIFF at the automatic setting to preserve quality. HDD pace is cheap these days, and I don't need a bazillion songs on my 10G iPod. A cable modem solves the download probbleme iTunes site. I use a G4 Cube. I burn at the max speed possible. I also use Roxio Toast Titanium for CD copying--, much easier than iTunes.
Isn't AAC supposed to be cd quality sound?