12 v. 15 PB
Totally understand your dilemma. Suffered from it myself. Looked at the 15" Ti and thought it was too old, no AE, last year's technology, etc. So I bought a 12" PB, BTO w/640K, 60gHD, AE card, took delivery a week or so ago (pre-upgrade...), got it, had a bit of buyer's remorse about the screen--thought it was just a bit too small. Thought about the separate monitor route but decided that defeated the purpose of the portability--can move it anywhere around the house with AE card, etc. Pretty much had made my peace with the 12" and decided I really liked it.
BUT THEN the 15" Al came out, and I agonized over whether to swap the 12" for the 15". In the end, decided to do it. Am sending back the 12", paying the 10% restocking fee, and my 15" is supposed to ship 9/23. It's my only computer and the 12" was just too small.
For what that's worth.