"Learn FX and compositing". I'd agree with that. It will definitely add a new dimension to what you do. I've been noticing recently how the boundaries between shot material, CG, graphics etc. are breaking down.
If you like the VFX side of things, then you might find a position as a VFX supervisor or such-like will get you away from the screen and out on set from time to time.
You could look at feature films. You'll definitely be working in a team, but you might end up rotoscoping someone's ear for 8 weeks only to have the shot dropped in the final cut. Commercials side is a bit more stimulating, if you like 17 hour work days ;-)
You can pick up a legit copy of Shake for about £200 these days. It's a very much 'roll your own' program, building tools and features for yourself out of simpler building blocks. You can learn the basics in a week. Although it's now unsupported and well past its sell-by, it's still used in many of the big FX houses, although Nuke and Fusion are gaining ground rapidly. (the transition's also pretty easy to manage, between these three)
If nothing else, then a knowledge of one of these node based compositers will change the way you use After Effects.