If you are running a lot of Virtual Instruments, your are going to need a lot of RAM, and the iMac just won't do it. Was helping some dude here at college on DP with a new MacBookPro laptop and 3GB RAM (the max for that ) and it wasn't enough. I think iMac holds less than 3GB.
Consider a Desktop Tower or another CPU along with the iMac just for VI.

Wise words indeed, thanks.. I have DP4.5 and could get an imac now and upgrade to dp5.0 and see if I get used to it, or wait till the new macs come out. And when the new version of Logic comes out, I want to see what that's all about as well. I think the biggest reason I'm thinking of waiting for the new imacs is I want to use a lot of virtual instruments, and the imacs have a limit of 3 gigs. but i'd like to stick with imacs, because, for this generation anyway, they seem to give the most band for the buck....I haven't been composing or recroding the last few years, but am eager to get back into it. I just want the setup to be as optimal as I can get it when I start back up.

I think it's the laptop that has the 3 gb limit. I'm on an intel iMac at work and it's maxed out out 2gb. It would work good, just limit the sounds you load.
The new imacs are pretty good. I had one of the G5 imacs, and every time I started ProTools the fans would come on full. I don't think this is a problem with the Intels.

From benchmarks I have seen the Core2Duo Macintels are faster than last years dual G5 Powermacs.

You probably won't run out of power any time soon. Max out your RAM, and record to an external 7200 rpm firewire drive.

I picked up a core duo mini for evalution, after running Logic pro, and Live6 for a few months I've decided to make it my primary machine.

Impressed me and I haven't even upgraded RAM yet.

So far no problems with sessions of 32-48 tracks, mostly virtual instruments, no need to freeze tracks.

I boot from an external firewire drive for a little performance boost.

8)

that sounds pretty good. Makes me hopeful. So how much ram do you have at this point, and what virtual instruments are you using? I'm considering a variety, MOTU Syphonic instrument, some NI stuff, Massive, B4, etc etc. Basically want a turnkey tool for doing a variety of composing, from songs to scoring etc.

gdoubleyou wrote: From benchmarks I have seen the Core2Duo Macintels are faster than last years dual G5 Powermacs.

You probably won't run out of power any time soon. Max out your RAM, and record to an external 7200 rpm firewire drive.

I picked up a core duo mini for evalution, after running Logic pro, and Live6 for a few months I've decided to make it my primary machine.

Impressed me and I haven't even upgraded RAM yet.

So far no problems with sessions of 32-48 tracks, mostly virtual instruments, no need to freeze tracks.

I boot from an external firewire drive for a little performance boost.

8)

So far I still have the stock 512MB, will be maxing the RAM very soon.

Since I have Logic Pro, I don't have a great need for 3rd party plugs.

I do have some Romplers on my powerbook, haven't decided what to do yet.

For UB support some products like Plugsounds came out with a new instrument.

The Native Instrument romplers would require me to Purchase the full version of Kompakt, plus iLok. One of the sample companies decided not to go forward with the NI rompler, and will be releasing with a different player.

I have a few of the UB freebies, Crystal, automat, but the Logic Instruments pretty much cover all bases for me.

I priced out the Native Instruments offerings and determined I would be paying over double the price of Logic pro.

And since the logic instruments are integrated into the source code, it makes for an easy Intel transition.

8)