I also hated the 16/32 bit classic Megaman titles. But after playing them a 2nd time, and then a 3rd time, my view of them changed.
I particularly like MM8 best, even if it falls down into the very easy category. The level of graphic detail put into MM8 is undeniable. I really wish it had more extras because the game can be a bit short compared to its contemporary X counterparts.
I bought MM8 through Amazon two years ago because I wanted to play anything Megaman on my PS3.
The only weak link I see in MM8 is the music, but at least it can be soothing!
As for MM7, I respect it so much more now. It had a pivotal role in MM's character, and the game itself was outside the usual happier tone other classic MM titles offered. For me, it's the black sheep of the classic games (not counting R&F2 on wonderswan) but I like it even more for it.
MM&B is special. I have mixed feelings on it, but it's still very enjoyable. The ammount of ablities the game offers can keep me entertained for a long while.
But as far as replay value goes, MM10 hands down. I hope nothing less than MM10 replay value if they ever make a new entry in the classic series. :D