Mandriva / Mageia

have been using mandriva for a couple of years - great community. Lots of hardware support and good application of the kde desktop. Things are where I expect them to be having come over from windows. Making for an easy transition.
have had driver issues with ubuntu on a couple of laptops. and found life easier using 32 bit.
Mageia is a community fork of mandriva

http://www.mageia.org/en/

http://www.mandriva.com/en/

an downloading mandriva 2011 64bit has there looks to be some improvements .

as for antivirus - I use clam on Linux machines . in this world your mad not to have something, as even if it doesn't effect your Linux box a usb stick/email may transfer it to a windows device....