i would concur that unless you are a computer whiz and actively keep tabs on all your processes and network traffic, a anti virus is worthwhile. unless you never download anything(ever) you cant be certain. the software firewall and the hardware firewall are indeed your best proactive defense against viruses, but there are 50,000 viruses created everyday. and to say you know about all of them is foolish. i would run your antimalware at least once a week. and occasionally do a scan by another vendor, to see if it picked up anything your primary did not.
as for your email suggestions. first LastPass doesn't send password resets to your email so i am unsure as to your supposed benefits of using your own domain, the only thing i can think of is that it makes you a smaller target, but again that is only security through obscurity, which i don't hold much faith in.
my contribution to this thread is to increase the iterations used. it is defaulted at 0, yet LastPass recommends between 1-1000 with 500 as a healthy balance