I was about to give this system the "thumbs up" (see below) then I came across one very important detail.
Some of the Intel Q8300s have virtualization VT-x support and some do not. It depends on the part number (see the link under ordering info toward the bottom of the page).
The VT-x makes virtualization like VirtualBox and KVM run faster. IMO virtualization is becoming increasingly important. On your spec system you have plenty of DRAM and Disk for virtualization, so you could for example keep a virtual Windows OS around and a virtual Debian or whatever.
I haven't run or seen any benchmarks in the past 18 months, so I can't honestly tell you how much slower the virtualization is without VT-x. OTOH you have 4 cores and it's extremely hard to keep them all busy - so perhaps it's a don't care.
This is an interesting looking SFF system and I don't think you'll experience any vid driver problems. The GT220 isn't high performance but gaming isn't on your list, so that doesn't matter much. Nearly all GT220s have a fan which adds to system noise.
Is seems to have an HDMI and a VGA connector - no DVI. You'll get a better image from the hdmi socket. If you are buying a monitor separately get one w/ hdmi. Otherwise you can buy an hdmi cable plus an hdmi to dvi adapter (buy online the store prices are outrageous). The adapter is just passive wiring so buy a cheap one, like $5.
I've purchased at deep surplus several times - no problems. BTW *DO* get your cat 5e/cat6 enet cables and a couple usb extension cables when you order there - dirt cheap, good quality.
The quad-core always sounds better, but the fact is that often w/ a fast processor the number of runnable tasks rarely hits 3 or 4 ,so in practice you won't "feel" much/any improvement over a dual core. UNLESS you have specific multithreaded or multiple independent tests running often. Still the Q8300 is relatively low power (95W TPD & a lot less at idle).
It would be nice to know the gigE and wifi chips involved, but it's unlikely to be an issue IMO.
The 1TB drive is plenty. It's a 5400rpm/lower power drive, but that's appropriate. Lot's of storage but not blazingly fast.
Acer generally has decent build quality - I'd prefer them over a gateway comparable.
The system seems to be being phased out just recently. There are 5 reviews at NewEgg in their archives:
Among the "Cons" we see ...
There is no CD/DVD eject button. So you'll want to make a desktop launcher for "eject /dev/sr0" and "eject -t /dev/sr0" commands. A couple arrived w/ damaged drives, not a system criticism IMO. The bright blue led caused some comments
I'm personally would build a system before buying, but many would rather buy. I don't see any problems w/ this acer. In the Small formfactor you have no expansion capability, and the custom mobo may limit your expansion too. So consider what changes/upgrades you might want to make over the years carefully.
The LGA775 socket is past it's peak, but the CPU & Mem you are buying give good performance at a good price point. You have no realistic CPU or DRAM upgrade path, but few ppl need this. The 8GB should be fine on Linux for years.
The CD/DVD drive is pretty vanilla, but you can swap it out if needed. The 5400 1TB drive is a good choice to keep the power/heat down and with all the Linux DRAM/disk buffers you shouldn't feel speed is much of an issue for development. The GigE is ideal. If you can get 802.11G on the wifi that probably exceeds your ISP speed for a few years.
I find the KB & Mouse to be critical for SW development so yo may want to replace those (maybe the OEMs ar fine) - but they aren't a large part of the investment anyway.
The probable lack of VT-x is the only negative I see.
Ask on the forum how others KVM/VirtualBox perform w/o VT-x. My guess is that it eats up more CPU time, but performs OK. That is fine when you have an extra 1 or 2 cores mostly idling.