1000D with better lens or 500D with kitlens?

Hello,

Six months ago I owned a Eos 1000D with kitlens and lenses from older Canon camera. The kitlens (18-55 IS) was ok, but I was more satisfied with the other
lenses. Unfortunately, some nightvisitors came to my house to collect my
equipment so I can start all over again.

Because of a limited budget, I was thinking about the 1000D body together with

the Sigma 18-50mm F2.8-4.5 DC OS HSM Canon. But when I was trying the 500D at the shop, pictures on the lcd-screen seemed a lot better (Both with kitlens-to try with the Sigma was not possible). Is this because the lcd(500d) has a lot more dots
than the lcd on the 1000d? Or is the sensor/processor better?

The 500D with kitlens will cost me more or less the same as the 1000D with the
Sigma 18-50mm F2.8-4.5 DC OS HSM Canon.

Thanks for advice.