Okay for the processor, this mobile 2400+ XP will do wonders, first of all since it's mobile, it runs cooler, and when things run cooler they overclock better; basically what I'm saying is you can overclock this thing from 1.8ghz to 2.3ghz or more fairly easily just using air. Here is the CPU- http://www.newegg.com/app/ViewProduc...103-439&depa=0
For the mobo, the Abit NF7-S has the most overclocking features and is the most stable. Here it is- http://www.newegg.com/app/viewProduc...127-166&depa=0
Now the CPU aforementioned is OEM meaning it is just the processor, you will need a heatsink and a fan, here is the perfect one for this application- http://www.newegg.com/app/ViewProduc...106-037&depa=0
Good news it's on sale!
Next we have the graphics card, I recommend the Radeon 9800 Pro, this thing hauls arse and is great in most of the newer games on between medium and high settings. Here it is- http://www.newegg.com/app/ViewProduc...102-297&depa=0
Now for a CD-ROM I prefer samsung, here is a good one- http://www.newegg.com/app/ViewProduc...151-046&depa=0
The color depends on the case, you can always paint the faceplate also.
For the floppy, this one will do just fine- http://www.newegg.com/app/ViewProduc...103-203&depa=0
again it can be painted to match your case.
And for your case, it all is personal preference. Lets see how much money there is left to help us decide.
Graphics Card= $239.00
CPU Cooler= $24.99 On Sale.
That Tallies to: $449.74 and that's before shipping. So that leaves $50 for a case. Not to bad. Here is a nice one for $50- This exactly the one I have btw- http://www.newegg.com/app/ViewProduc...156-142&depa=1
It comes with an awesome psu and some fans, but I love the cobra eyes on the front that glow with hdd activity. There are two other flavors, this- http://www.newegg.com/app/ViewProduc...156-145&depa=1
and this- http://www.newegg.com/app/viewproduc...156-140&DEPA=1
The only differences are the color schemes, I hope I helped, I just wasted a good hour doing this for you... I think I set a post record as well.