That's the thing, Xlobby is already setup to use Foobar/Winamp, so there is virtually nothing to tweak...only the buttons you would use to control either one.
Zoomplayer is not used as Winamp (not sure about Foobar, and there are most likely a few here who would endorse it) is known as one of the best software music players on the market (though it's free). Steven has already taken what is considered the best...that being Winamp/Foobar for music and Zoomplayer/Theatertek for DVD watching and essentially made a shell around them. The integration is done...you just have to learn how to make it look good ie...skinning.
If you go another route, then you will be spending time tweaking Xlobby to work with the player you decide to go with to get all the functionality that has already been integrated.
Maybe I misunderstood you...in your original post you said this:
I'm actually supposed to build a media PC for two friends after I'm done (for free) and really want to strip things down and keep them as simple as possible from a config standpoint.
If you want to keep things stripped down and as simple as possible...why re-invent the wheel?
But then you said in your last post:
Well, the goal in my project is not to have this flexible tool that I can endlessly tweak to my own needs, which seems to be what most people here are after.
You will find that most poeple aren't playing around with the basic functionality. Granted, Zoom nor Theatertek handle .mov file well so people resort to WMP classic. Poeple tweek for multi-zoning, TV capture etc....things that stretch beyond the basics of xlobby.
Then you finish off with:
I'm trying to build an off the shelf, self-contained media center (ala Escient's fireball/dvdm products) that I can then "can" and replicate for two friends.
Which again would lead me to ask, why change something that is already working well...create a bunch more work for you...taking away aspect of other areas of Xlobby that can be achieved...and create an even more impressive, more versitle system for your friends?
Bottom line though, each to their own and good luck should you decide to go that route. In the end, it's all a learning experience.
Hope this was helpful.