I've got a TH42PX60 (old model), had a couple of purple snake issues (don't ask, fixed in later models) but largely it has been excellent and when I upgrade to a full 1080 set I would definitely look at Panasonic first.
Before I bought my panny I spent hours online researching 'purple snakes', eventually decided to buy it with a 30day no questions asked returns policy so I could check for snakes. Never seen one to this day. I'd highly recommend panasonics to everyone.