People are confusing strains with growing mediums.
Hydro of course is the best. It will yeild 4 times what soil will in the same amount of time. But it is spendy and difficult to maintain and operate.
There are too many variables to say one method is better than the other. People with 10k setups can grow shit weed just cause they dont know what they are doing with nutes or have insufficient light. And a kid with a 300 dollar HPS lamp in his garage who knows how to water, feed, and scrog properly can produce a product of the finest calibre.
As for strains, I am pretty sure the strongest weed on the block right now is Jack Herer.
http://www.seedsdirect.to/cgi/callst...Seeds&num=ss03
Its a hybrid of 3 of the strongest breeds known to man.
And of course NL#5XHaze
http://www.seedsdirect.to/cgi/callst...Seeds&num=ss14
Blue-Berry
http://www.seedsdirect.to/cgi/callst...Label&num=wl05
And everyone elses favorite for some reason... white widow.
http://www.seedsdirect.to/cgi/callst...Label&num=wl08
The only reason I think white widow is so popular these days is because it has a quick flowering time, making it ideal for indoor and outdoor growers. Its good, but there are much better strains out there.
There are boutique quality seeds coming from BushyOldGrower (of Overgrow fame) that I think are going to be just killer. The yeild off his strains are insane. Colas that look like two litre bottles of coke, IN GIRTH. Absolutely absurd. They are called Bogglegum and Bogbubble. Cant wait to get my hands on it.
So much weed, so little time.