best virtualization

hi guys, what would be the best ubuntu derivate /virtualization for my xeon with 16gigs ram and 2xtb SAS.

I totally want ubuntu! or should i maybe take xubuntu or w/e?

what im going to do:
*much torrenting also run rtorrent and a few scripts
*high end encoding
*run a few win programs via wine

so im looking for a OS which can handle much cpu usage and memroy usage, can you help me out?

cheers