If I had a dollar for every time this question was asked at TFP I'd be as rich as Bill Gates. Someone should put up a sticky thread on this but I suppose stuff changes so fast it's probably pointless. Sorry for the rant. On to an answer...
I haven't done any video editing in awhile but "general use" and video editing never went hand-in-hand. Assuming you no longer need an IDE RAID array to keep up the data transfer for capturing and editing, I fallback to your general use need.
Unless you feel like building a box, I'd just go with a Dell. If you want to tweak everything out and have smoke come out the back, you'll probably want to do some reading about the myriad of AMD and Intel chips, FSB, and all the other peripherals. Since you are short on time, this may not be an option for you.
I always buy a name brand, however it's the question of who is a name brand? Asus and ECS are both name brands but I'd never buy an ECS system board based on the experience of others. But do you need to buy a SoundBlaser Audigy instead of using the built-in 6.1 channel audio of an nForce system board? Prollly not.
For me, I recommend Dell for the support. I'm sure we all have horror stories about Dell support but you know there is someone to field your complaint. Systemax might be a fine system (I have no idea) but I'd build my own if I didn't go the route of Dell.
Here's what I have. It's a couple of years old but relatively current as far as Athlon XP systems go.
Asus A7N8X Deluxe (v1.1)
2x256 MB PNY RAM (DDR400)
ATI Radeon 8500
Athlon XP 2000+
80 GB ATA drive (8 MB cache)
It's got built in USB 2.0, Firewire 400, 6.1 audio, and dual 10/100 LAN. It works plenty well for everything including Battlefield 1942.
What would I change? Faster CPU although I'd need to get a new mobo that supports the Barton core of the Athlon XP. Perhaps utilize the SATA RAID controller for faster disk performance. Faster video card. I'd go with a Athlon XP 2800+ and the latest ATI or nVidia card and I'll probably be OK for the next two years.
If I were buying something new? Hmm. Things are still changing with the FSB 800 and new P4s. PCI-Express is all the rage but I'll need to wait for a compatible video card. I'm also waiting for SATA drives to transfer more than 150 MB/sec. So, I think there is some catching up to do on the peripheral side and it'll cost you.
And whatever you do, don't run Windows.