It's hard to say what is the best pill I've ever had. Most good pills on the market have always been the same strength or close to in my opinion and I reckon what makes a good pill is the mood your in at the time. Though here are my favourites:
Double Stamped Red HQ: Quite overratewd with a short 2.5 hour peak, but they were very clean and were great to dump while playing Daytona at the arcades. A lot of myths also spurred about the contents of this pill, but I'm sure it had MDA in it somewhere.
Pink Panthers (white): Very nice smacky pill that put me on my arse. Someone told me it was actually MDE (not MDA), but who cares, they were a real thumper...and only a psycho would double dump these babies.
1's: This is the best pill I've had this year so far. Ppl reckon the hearts and green fish are better...but nah. These were the overall most pleasant pill I've ever had in my life I'll have to say. A long lasting peak that was not overpowering but just incredibly nice. I was even in the shittiest mood when I dumped this and it still picked me up to no end. And not many pills can do that.
Pink MX: A bit of a mumbly pill, but quite a strong hitter.
Superman: Very floaty peak which kinda reminded me of the HQ's, but it had a longer peak. These are still around and are worth a buy. But be careful, heaps of dodgey ripp-offs abound.
German pharmeceutical MDMA: These were the best pills I ever had. They came in prescription packs and were fucking huge chalky pills. Other than pure MDMA, this was the SHIT!!
Almost forgot
Blue Sky's: These had the BEST come up I've ever encountered. They weren't the strongest, but by god, they were just plain NICE. Only the 1's beat this for me in niceness