You're correct in that you cannot infer much about a company's DLSRs by the lens quality of their P&Ss.
Much also depends on what "best lenses for reasonable prices" means.
The limited number of Zeiss lenses in the Sony line are fabulous but they
start around $1200.
I suspect you'll find much the same in the very complete Canon and Nikon lines (ie: if you're not going to spend $1000+ per lens it doesn't mean much to talk lenses that cost twice that.)
spend a little time at
Photozone.de, one of the best lens evaluation / test sites. It's not a complete listing but there are many Nikon and Canon lenses tested.
Compare the lenses you might actually buy rather than each company's super-duper-bestest one.
