One thing I've had a problem with is that although sometimes I like to play 1.5.2 or other older versions of minecraft, I currently have to manually swap out my mod setups for each version. I got an error loading 1.6.1 about conflicting mods when having both the 1.5.2 version and the 1.6.1 version of Rei's Minimap in my mods folder.

 

My idea is to make the mods folder per-profile, so that I can have my 1.5.2 mods with my 1.5.2 installation, and my 1.6.1 mods with my 1.6.1 install, no switching needed.

 

I really hope this is something possible to do, and I'm grateful for all the hard work the Forge team puts into getting Forge to work with each update.

Alternatively, set your Game Directory to the %appdata%/.minecraft/versions/{current version of forge you're using} folder. Then you will have a different flavor per setup.

 

Then...

...Space-related (galacticraft) mods in 1.6.2Forge_Space

...Feed-the-Beast mods in 1.5.2Forge_FTB

...Hexxit in the 1.5.2Forge_Hexxit

...Client-only mods in {minecraft version}Forge_ClientOnly

 

That's how I'm using it. I don't need all the Feed the Beast mods when I'm playing Hexxit. I don't need all the mods when I'm connecting to a vanilla server where I can only use things like minimaps and armor displays. Each version tells me what type of game it is I'm playing and what version of Minecraft is being used.