Newbie With A Couple Of Questions Options

[dalty52]

Hi, I've decided to invest in a quality, but affordable audio/MIDI sequencing setup. I've pretty much made up my mind on getting a MOTU 828 audio interface, yet I'm still undecided as to what computer to buy and what sequencing software I should get. I want to be able to sequence a professional sounding background track and have the ability to record digital audio over the sequence(i.e. possibly some Jingle writing or even songwriting demos). I've been looking at DP4 and Logic Platinum.......any comments regarding these two programs? I know that I can sync music to video using Logic. Is this possible in DP4, as well? I've heard the learning curve on Logic is high, so I've been thinking DP4 would be more suitable, however many say Logic is the way to go, regardless of the learning curve. Am I sacrificing a great by choosing the program with the user-friendly interface?
As far as the computer goes, I've been looking at the G5 dual 2GHZ with 1GB of Ram. Would a dual 1.8 with 2GB of Ram provide better performance? Also, if I were to purchase a powerbook instead(obviously for the portability factor) would I be sacrificing a great deal of performance? Any comments are greatly appreciated. Thanks!

Dalton