i would probably go for some kind of pedal/desktop FX/modelling unit, if you are going to be using headphones then the speaker and power amp is a bit of a waste of space, I have a couple of very nice amps (all valve) but 99% of the time I use headphones and a desktop modelling unit, (i went for a Vox Unit, the tale of which is Here)
As you are tech savvy then one of the clever modern modelling units would be a great place to start, and if you find yourself needing to play live then it can either be run straigh into the PA or you can pick up something like a powered speaker to run it into (which is getting very popular at the moment. look at units from Boss, Line6 etc, the modern Zoom units are pretty good as well at the moment, much better than when i first used them back in the late 90's and really quite affordable, most of these units work great running into amps as well and some have USB outputs for recording.
Matt