You're very welcome!
To answer your "strength" test-question:
Well.., no.., but in fact, some people make a living off testing such things for you. Also, I sincerely hope you are not receiving too much malware samples to test that thoroughly in the first place
In short, there is no "best" AV, especially for end-users, only 'sufficient' and 'totally useless'. (lol, sorry)
To aid you in your quest for the most fitting AV solution for your needs:http://www.av-comparatives.org/
is widely known for it's clear and easy to interpret tests.
Also, you could spend some time on VirusTotal.com to see with your own eyes what scanner A finds compared to scanner B.
It's very wise of you to have a second opinion available though! (Although the one in VM = XP mode, cannot be relied upon to scan your Win7!)
Active AV can be successfully operated alongside on-demand Anti-Malware solutions like MBAM for example, and will not conflict as long as you keep the active protection module from MBAM disabled.
I personally also like to use LiveCD's once in a while, but I'm paranoid, I have to admit. See Kaspersky Rescue CD and F-Secure Rescue CD on Google for more info on those ways of scanning, they're free (well, apart from a CD-R) as well.