I just removed Windows Live OneCare from my Computer, since Microsoft has discontinued it. I have installed the following:
Microsoft Baseline Security Analyzer
Spybot Search & Destroy
Hi-Jack this (yes I know that this is a very powerful tool, I have only used it once for a really bad infection)
Is this overkill? My wife thinks that I have too many spyware programs on the computers.
It is not necessarily overkill, as long as you don't keep too many of them running resident at the same time. That would be bad (may cause conflicts). What I would do is run the antivirus program in the background, all the time, and the firewall of course always on, but the other stuff I would only run on demand. This would decrease memory usage and still provide decent protection.
Microsoft Baseline Security Analyzer is a decent way to keep up with Windows updates and other such things, and doesn't conflict with other 'security software'.
I have set up Avria, Spybot, and Windows Defender to run overnight scans.
Also, is it a good idea to run mutiple scans at once? or run them one at a time?
No, never run multiple scans at once. They slow each other down a great deal, and can cause many problems. Run them one at a time.
Personally, I think running overnight scans is overkill, unless you have really unsafe computer use habits for some reason. As long as you keep the antivirus realtime monitoring on, running overnight scans with it is somewhat pointless.