To be honest-I think it depends on two factors...
Firstly-How much are you really going to need to push ISO up?
If what you really want is family portraits/baby shots etc,then to be honest i cant see too much low light work there..
Second-Obviously the 500d's 15mp is somewhat higher than the 1000d's,but to be honest unless you plan on some seriously large prints,then you wont notice it too much.
(I have poster sized prints from a 1000d and they are just fine)
The 500d is obviously a superior piece of kit-Digic 4,more AF points,faster shooting etc..The question is,are those differences enough to justify pretty much double the price tag for you personally?
In the majority of situations,the 1000d is capable of producing images that are pretty darn good.
The money you would save over a 500d kit could go to getting lenses/flash etc,which in all honesty are far more likely to have an impact on your photos than the difference between the two camera bodies.
Whichever you choose-Cant see you being too dissapointed!
