It's been already a while in my rig but Axe FX II (+dedicated pedalboard from Fractal Audio) has been one of the best investments ever. With Axe Edit 3.xx I can dial virtually any guitar or bass sound I want quickly and with ease - and save them as presets for later use.
The other investment is a step to opposite direction; real Hammond organ from the early 70's. Digital organs sound great until you hear the real thing. :)
Axe FX II is almost as good as my best real guitar amps but it's million times more versatile.