Some more questions you need to know the answer to before you decide:
Do you want just music? Video? Karaoke?
What is your hardware going to be? (motherboard, memory, sound card, video card, sound system). I have found that if your only going to do music, just about any PIII system with 256mb ram will work. If your going to do music and video, then you need to step up the video card to at least 64mb ram video card and 512mb of memory. Make sure your system can use Windows Media Player 11 as most if not all jukebox software uses WMP 11 for its architecture.
How flashy do you want it to be? Lights? Flashing Lumin Disks? Use of a BetaBright?
How much time do you want to invest? ie: will the wife or girlfriend get mad

if you spend too much time with this project?
How much $$$$ are you willing to invest? ie: will the wife or girlfriend get mad

if you spend too much money on this project?
How much of your personal investment will you be willing to make into this project?
What ever time and money you put down on paper, add 25% more. Just for tweaking and the off chance you mess something up!
Lots of great and not so great ideas on the BYOAC forums. Some are big and bulky and some are smaller and have manuverability (ie: able to put it in where your wife or girlfriend wants it VS where you think it should be) (see the trend with my statements?

)
After you answer all the questions from previous posts and this one, then you will have a more clear understanding why they were asked!
Hope this helps!

Fordman