May I share an experience I just made?
A sticky thread says: "Dont use ModLoader.", "Don't use MC-Patcher." and so on,
but there is another way, to make harmony between all those things:
The Problems, you may have with MCPatcher is from incorrect usage, but I will explain it:
Everytime you select a mod with MCPatcher to add it goes to the top of the list in the MCPatcher.
So if you select Modloader, Forge, PlayerAPI in this order and then click Patch, it will first use PlayerAPI, then Forge, then ModLoader and then the other MCPatches.
That's of course the wrong order, so before clicking Patch, you must sort the mods.
The right order is (from top to bottom):
ModLoader,
ModLoaderMP (not tested, but I think, this place),
Forge,
PlayerAPI (if you use this, make sure it is newer than Forge to make sure it supports your Forge-version),
Other mods (forum admins, please feel free to add more sort-dependencies),
MCPatches.
Another important thing is:
I you add more mods later make sure to move them below PlayerAPI to keep the sort order.
Also important is to keep all the checkmarks for all existing mods to install them again. I'm not sure if they are kept if you don't but it will inform you about upcoming conflicts.
I don't use Optifine, so I don't know where to put, if possible.
@admins:
I don't say that this is the best method or even applicable, I just discovered the fact, that the sort order may be the cause of so many problems that some may see the MCPatcher as the problem, but I think, it's all about the sort order of the list. Please comment.
About the META-INF folder. I'm sorry, I should have expected this. I didn't use Forge in my bukkit server, should I?