as the others said, start up with the core. MY personal advice, don't start to fancy, as usually LMCE doesn't work out of the box, when picking modern hardware. for the core, your CPU might be over the edge, RAM... pick some cheap reliable, like Kingston. Be careful with the graphiccard. Keep to advices of the pros like Andre and Thom as these guys now what they are talking about !
Think about using 2 hard drives, a smaller speedy one (160GB, aprox. 30-40USD) and a data drive so you don't have to take much care about your media data when reinstalling (at the beginning, there are usually more than one).
The DiNovo wont work out-of-the box... so better order that on round 2. USB/PS2 works ALWAYS .
And... do NOT forget about the wiki => http://wiki.linuxmce.org/index.php/Hardware
The more you keep to "working" hardware, the more fun you will have with LMCE. BUT... getting stuff working
might be fun as well, keeps feeling your pro-like! ;O)
Enjoy your trip with LMCE...