I've also tried the excellent AmpleSound Guitar Martin VI which sounds excellent but then I'm limited to one guitar sound unless I buy a number of their VI's which is too expensive.

I've tried using Xpand!2 in Pro Tools First but it just sounds like a harpsicord, as there is no option to add the all important articulations that make it sound like a guitar. So I'm constrained to using a MDI controller or computer keyboard and whatever VI's I can get my hands on.

I'm not a guitarist so (in the short term anyway) I'm not going to invest in a guitar/bass, learn to play and then record an audio track.

Another area I'd really like to get better at is creating better guitar/bass tracks using MIDI and a suitable virtual instrument.