My last couple of computers were custom built using parts I put together from Newegg. And although I was overall satisfied with the results, I'm just not that into doing all the dirty work by myself anymore. Has anyone had any experience with one of those websites that specialize in putting together a custom computer?
I've heard of Uberclok, DigitalStorm, and iBuyPower from an article I read on IGN. Any other reliable services?

The main two I'm familiar with are iBuyPower and BuyXG. I don't have any first-hand experience with either, but I've heard more good than bad about both.

Falcon gives you a lot more customization in their rigs than say Dell.

iBuyPower is a great company, because it gives you the flexibility to choose parts like you would if you were to build it yourself. The fact that the company buys the parts from component manufacturers in bulk makes it an even better deal, since it's a lot cheaper like that. Sadly, there wouldn't be much in the way of support, because if you were to buy the parts yourself, each component would have its own support line you could use.

Err, I dunno if I suggest spending way over what you'd spend on custom parts, esp. in this economy.
A pre-built pc would take longer to get to your house then say a bunch of parts from Newegg ANYWAY, and you could have it built in a hour.

Seconded.
I notice that Newegg's FAQ states that "Sorry, Newegg.com does not build, assemble or test computer components.", but most local parts suppliers in Australia offer to build PCs if you buy all the parts from them.
If you have other places that you used to buy parts from regularly,, though, try calling them up and ask.
This is good for most small businesses: it means you're buying all of your parts from one place (therefore increasing their profit), it saves on returns (as they can test all of the parts before they ship it to you), and it should save them money on shipping.