My philosophy exactly.

I'm dying for a new machine right now but can't decide how to go about it. I have the two in my sig - the iMac is great, but I want a bigger screen. The PB G4 is quickly becoming dog-slow at EVERYTHING online... too much Flash on the darned interwebs these days!
I can "trade" my iMac to Best Buy for $517 (a GREAT price, IMHO) and I can sell my PB on eBay for $250-300. That'd give me $800, but I can't decide what I'd want - a base iMac ($1149 on ed. discount) or a refurb 13" MBP ($999) or the new white Macbook ($949, and new). The iMac is WAY faster, but the Macbooks are portable... my wife has a year-old Macbook, but that's hers - I don't get to touch it very often (she uses it for nursing school). What to do, what to do...