Mac For School/recording, beginner looking for help Options

[sleepparalyzed]

hey all...new here to the mac music forum...was seeking some advice on getting started. i'm thinking about getting an imac g5 for school as i will be majoring in music with a recording emphasis most likely. im guessing i will probably start learning mic techniques and the ins and outs of pro tools my 2nd or 3rd year. this will be used for school (word processing, presentations, etc.), making electronic music (not hard trance stuff...more downtempo/trip-hop like bjork, radiohead, boards of canada, etc.), and recording. here are the specs with a student discount:

$1,399.00

17-inch widescreen LCD
2GHz PowerPC G5
667MHz frontside bus
512K L2 cache
512MB DDR400 SDRAM
160GB Serial ATA hard drive
Slot-load 8x SuperDrive (double-layer)
ATI Radeon 9600
128MB DDR video memory
56K internal modem

i know i need to upgrade the RAM...i think if i order online, i can upgrade the RAM to:

1GB - 2 DIMMs for $112
1GB - 1 DIMM for $157
2GB - 2 DIMMs for $427
don't understand the 1/2 DIMMs, anyone know about this? not sure which one to choose out of these three.

do you think the 160GB 7200rpm hard drive will be ok?

as far as speakers, should i be getting low-mid price range monitors or just high quality stereo speakers and a sub?

as far as software goes, i'm thinking about pursuing the MBox with protools LE and ableton live lite 4 and reason adapted. i'll probably get an edirol pcr-a30 for a midi controller as well. can i use reason and ableton and pro tools all at the same time? does ableton support midi? i'll probably end up getting recycle for some editing too. any other software options?

all comments/suggestions are welcome.

thanks in advance for your help,
greg