I have MSE running alongside Norton 2011 with no problems. I also use MBAM on-demand scanning. Each security suite or program detects in different ways and some are better at cleaning what is found.
MBAM is especially good at, well, malware such as bots, trojans, fake AV, and worms that both MSE and Norton might miss altogether. In other words practice some old advice concerning security..."Don't put all your eggs in one basket."
From Spyware Blaster
Must co-exist peacefully with other software
We recognize that there is no complete solution for the ills that plague computers and software. And we understand the desire and need for an appropriate layered defense.
SpywareBlaster is built to work with any other software on your PC. You can add it as an additional, powerful layer of protection to whatever software you already have installed. In fact, SpywareBlaster's protection works well to augment nearly any combination of security and privacy tools, by focusing on prevention.