Hello, as you all can see I'm quite new here. Nevertheless, I've been following this topic for quite some time. I'll just give you my opinion now.
Yes, I think the peloton is cleaner than it was 5 years ago. The main reason? Belgian cyclists were blown away wherever the road got a little more steep than in the Flemish roads. We were good in our classics + Paris-Roubaix, but in the hilly classics like LBL, FW and AGR, we were blown away by a Spanish armada (notable names like Sevilla, Mancebo, Valverde, Astarloa), Italian riders (Bettini, Rebellin, Di Luca or how about the Gewiss-Ballan team? ...) or even German riders (Telekom). It's new for me, as it is for our tv-commentators as well. I've been following cyclism since the late eighties and cycling never looked so good for Belgium in general. My dad tells me it was like this in the seventies.
In the last Classico San Sebastian, 4 Belgian riders were in the top 10...this seems like another era, a cleaner one in my opinion.
What about Gilbert? Well, you should take a look at his perfomances on the dutch wikipedia site
http://nl.wikipedia.org/wiki/Philippe_Gilbert_(wielrenner). He didn't come out of nowhere. In 2006, he won the very difficult race 'Omloop het volk' in a Merckxian way...People like Merckx and other famous ex-cyclists told us back then he would become on the best of his generation at a certain age and they were right.
Take a look at his results this year, yes it seems unbelievable and too good to be true, but it is always in the same way. He has been training on these kind of finishes for the last 3 years. He never does a solo of 50k like Cancellara did (or like user-Museeuw did). Solo in AGR? 500 meters. Solo in FW? 350 meters. Solo in LBL? 0 km...solo in TDF stage 1? 100 meters...
It's a poker game and he wins often this year, probably due to a good morale and years of experience of timing. He was in front in Milan-San Remo, Tour of Flanders and last year's world championship and three times the peloton took him back. Today in the Eneco Tour, it was almost the same thing.
So my point: Do I think he's clean? Yes, I do, or at least as clean as the rest of the world top :x. Cavendish is the world's best sprinter, Cancellara has been a dominator in time trial stages for years (maybe Martin is becoming the new champ here), and Gilbert is specialized in hilly stages. Each discipline has its champion. And, I'm sorry, but saying someone is doped based on their number of victories is quite ridiculous.