The only thing I have left is the last boss to beat. I am just wondering what level I should be at and what things I should have to prepare for the last boss. I'm at around level 60 right now. I also have all the summons except one of the bahamuts.

Sounds to me like you're perfectly good to go o_O
Don't even have to be that high of a level if you're used to the materia system o_O Have at it and goodluck

Got all the master limit breaks and the ultimate weapons just for the sake of 'completing' the game more? :D

<font color=red face="comic sans ms">You should be able to complete the game at level 60. I've managed to complete the game at level 44-45, so it's not too bad. If you think you haven't done enough, you can level up more in the crater if you need to. Otherwise, you can just go back and try to do any sidequests you haven't done or anything, and get everything you haven't got.

Or, if you just want to complete the game now without worrying about getting everything and completing the sidequests and stuff, you can go and complete it now, it shuoldn't be too much of a problem. :D

Well, you have Knights of the Round. No problem. I'd link MP Turbo to Knights of Round. Makes it attack much more with just 5MP extra.

so comrie you say you have left out a bahamut, and you got knights of the round.. thats pretty odd but...still i suppose you dont need the bahamuts at all for the final battle,

just make sure next time your on lvl99.
with master materia and full stats

i heard that having lvl99 and full stats increases the last boss's HP by 3x!! or 2x if your on lvl98

should be challenging

Not really. Sephiroth's basically just mincemeat if you're on Level 98 or 99. It's almost sorta pointless that they double/triple his HP because at that level you can pretty much just have your way with him.

Hes not that hard. First time through I beat him at 64 with no KOTR or Omnislash. I just Bahamut Zero every chance and Highwind limit is cool. And kicks his ass with my cool Ultima Weapon.

I have never lost to the last boss so you should be able to beat him. No worry! ! ! !

I didn't find the last battle overly hard, but that terribly long attack that runs through all the planets is annoying. Only because it's so damn loooooong.