Data Execution Prevention: Req'd?

Smiles everyone. Am running a solar-powered, rocket-propelled Windows Vista
Home Basic operating system. Norton Internet Security 2007 pre-installed by
OEM for my benefit. So Vista has DEP available for Vista but is off by
default because of backwards compatibility I read. I put it up for awhile to
protect essential Windows and for IE7 to "help mitigate against online
attacks". Noticed IE7 shut down when ran the standard test at java.com to
confirm that I have the current runtime environment (which I do). I figured
I'd just turn off DEP (have to do this I realize now by command prompt
bcdedit) and wait. I'm just wondering if other such set-ups i.e. Belarc
Advisor, which may run things on your computer will not go if DEP is up and
running? Or if want to let's say get a-squared spyware to scan my computer,
will DEP block this? I have not the slightest idea about this and am bowing
to the knowledge of the eminences on this forum as to whether DEP is up and
running on their computers. Well, for that matter anybody, eminences or not,
because I can't guage how many problems, if any, there are with DEP and how
many Vista users do actually use it? Any feedback kindly appreciated? Will
check up on weekend if any answers. Thanks alot.