Even taking into account that it's 256mb more?

As for the HDD upgrade, if that's a user-serviceable part, he's better off buying it through a third-party vendor than through Apple.

HDD is not a user-serviceable part. If you need a big internal HDD, buy it with that option from Apple. For most people, an external HDD is fine and much cheaper.

I think you could consider a MacPro although the inevitable upgrade is just around the corner. What you can get for $3059 (very close to your budget) with educational discount is a 2.8Ghz Quad Xeon processor (minus $639.10 from initial asking price), 2GB RAM and ATI Radeon HD 2600 XT (256mb) videocard.
From there you can virtually extend your machine when you can afford it. Throw in more RAM, upgrade the hard drive and even the videocard when your son decides to game (and is old enough to do so).
Offcourse you must also get a monitor and the inventment of upgrades are well beyond your budget but maybe this option might work for you in the long run?

The OP said he 'plans on doing FCP editing in the future'

So this is not going to be a video editing box primarily

The Mac Pro is overkill - get the refurb iMac

my 2 cent here go for the Refurbished iMac 24-inch 2.4GHz Intel Core 2 Duo for $1.768 upgrade to 4 gig of ram and you have saved yourself a grand.

I purchased the 2.4GHz 24" imac from the refurb shop and couldn't be happier!
Still only has the factory shipped 1 gb of ram in it which will be updated shortly to 4 gb.

Gentlemen (and ladies?) Firstly I'd just like to say thankyou to all who took the time to pass on their thoughts and suggestions.

I'm currently leaning toward the standard 2.8GHz config with a 750Ghz HDD. I appreciated the comments re: refurb machines but for me you just can't beat that new computer smell [if you know what I mean ] Not to mention my wife would probably say "...you spent all that money and it's 2nd hand?"

I did consider the Mac Pro, but have decided that it's probably a little bit of over-kill for my requirements, not to mention the increased cost (especially over the iMac 2.8GHz - more on the cost later). The other reasons are slightly less hard nosed - I actually like the look of the iMac (I know, I know...that it looks pretty is not going to make it go any faster) and on the slightly more practical side, I really like the all-in-one unit being up off the floor, away from the inquisitive little fingers of my two sons (the study is at the top of the stairs without any doors to close it off). Not to mention that my wife said she likes the look of it (a big plus when you are thinking of spending thousands of dollars on a new toy!)

Lastly - and this was the most suprising - when I was crunching the numbers last night, my wife was curious as to how much this was going to cost. When I explained the cost differences she said "Well, if you're happy with the cheaper one, the money you've saved can go towards that iPhone you wanted." Happy, happy days! Assuming that it wasn't an idle daydream, I'll probably wait until around Xmas for the iPhone - stock availability may have improved by then, plans may have been further tweaked by the telcos [I see Virgin are now in on the act] not to mention that a 32Gb version might be released around about that time as well (maybe..possibly...hell you never know!)

Anyway, thanks once again to all those who responded.

Just so you know - the refurbished machines smell exactly like new ones

In the words of the great Australian poet, Kevin Bloody Wilson;

(Living Next Door To Allan)

Never discount the link between looks and performance.

Good luck with the iMac and I hope your wife's memory extends until Xmas. Oh and don't discount those refurbs - they come fully packaged and wrapped inside and out just like a shop-bought one but without the full sticker price!

You know what, no matter what you choose you will be out of date in 6 months... I always buy second hand desktops (on my third second hand iMac) and it's a great way to pay half price for almost current spec equipment.

Desktops seem to go out of date alot slower than notebooks... I always buy new notebooks... but alas... they appear to only stay current for about 6 months also...

I tell you what, I'm pretty much the same !

How do you know the Mac Pro is coming to the end of it's cycle? and If it is does that mean there will be a price drop of the current ones when the new ones come out? or will they just replace them and keep the price the same?

I'm really after a MacPro personally but it's a little too much of a stretch

You can get the single quad-core mac pro for $289 more than the top line imac. heaps more power

You also need an LCD to go with it

For me i'de gt the 3.06 because i cannot stand slow processors.. (i was brought up with VERY slow PC's!!!) but because i am a student and am really getting into video editing i'd really go for the 24" 3.06 Processor...
Enjoy your new toy!!! =]