Top 10...

Well, You see... I've only played (8 classic, 4 GB, Xtreme 1 and 2... And Some of X1,2, and 3 on emulator AND MM&B so that's 18 games + ZX = 19)
Basically, all MM games are good. Every MM game i like that i've played EXCEPT for MM5. MM5 is bland, and medioker. My top 10 i guess would be
1.MM3 (basically i love 1-4 and 6-8 But MM3 was the first one i beat...} really, i like MM3 because it added Things to the series. Rush, Sliding, all that.
2.MMXT2 (Mega man Xtreme 2) because of good replay value (to me), and it's fun. Changing from X to Zero on Extreme mode feel's so good.
3. MM7. MM7 and MMX3(MMX3 is pretty good with adding to the previous games, like zero and the golden armor.)MM7 does get a lot of hate; but i like it. 1: It has Screws, Which are a new addition that stayed throughout the series. And other things which make the game more than welcome.
4. MM4 And MMX (MMX is good, nuff said). It has good Decent RM's, Good weapons, and had a certain charm to it.
5. MM2. Pretty good game, It's not the best but it's very good to me. This would not be my obvious choice but if i had to for my life play it i would Definitely say yes.
6. MM8. Now, Mega 8 is probably the hardest MM game i played for me, since i didnt get to the fortress stages at all. MM1-7 were at a decent level for a kid like me who was 6-7 at the time could get to the fortress stages, and actually beat MM1 and MM3. MM8 does add choppy voices, but i didnt really focus on that. Pretty good/decent.
7. MM1. Probably this game is the 2nd/3rd hardest for me, (MM8 was No. 1 then MM&B). THis was the only other MM game i beat besides 3. (I almost beat 7 BTW and MM6, MM6 i got to the first wily stage MM2 i almost got to the 2nd form of wily, the alien one but you know). MM1 was the classic first one, the one that had the early things, like 6 RM's and stuff. There is MMPU and the legend of Bond Man (Bond being the 7th RM for MM1 who would've been in MMPU.) but pretty solid.
8. MM6. MM6 is a good game to me, could of been better but you know...
9.MM&B. MM&B is probably the 3rd hardest MM game for me. Now, i took the easy route and played bass, but even then RM's can give you problems, and the stages can still kill you. Now, i felt that the game actually had a hard then easy then back to hard point. It felt like after cold, it got harder. Burner man, then the easy pirate man, then The hardest RM i swear to gosh Ground Man, I got stuck there so much on the RM... Then at tengu to king 1... It felt so simple. The RM's. I had trouble with Astro's battle... but you know.

10. Mega man; the power battle, And MM2: The Power Fighters. These 2 are Basically Mega man fighting games. MMTPB lets you play as mega, proto, or bass; and you can fight MM1&2, MM3-6, And MM7. MM2TPF lets you play as the first 3 characters, and Duo. Then, there is 3 missions you play, which have their seperate RM's.

Phew. That was pretty hard (man!). Anyway, About the X games, X1-3 i've played some of annd talking about what i've played of it. MM Xtreme 1-2, Xtreme 1 i only got to sigma 1 right now, and Xtreme 2 i basically beated. MMZX is another game i've played, which is ok...
Then... Mega man Battle transmision. The only MMBN game i've played. Suprising i played the one thats like classic MM.

And the worst MM game ever (which is like 5 out of 10 or 2.5 stars), Mega man 5. MM5 is not bad, just mediocker. Now, i played it before and thought it was fine, but now it's bland to me...

And done. finally