remember tone changes with volume.

Another option is to get a Pod and set up as follows.

Guitar into pod

Pod into FX loop return (bypassing the Marshall preamp) and use the Marshall power amp cab combo.

Another thing to try is a Boss OD-20 which dose everything from a tube screamer / blues driver to megametalmoltenmeltdowndroppedoctavekilleatdeath distortion (if you know what I mean). It took me a while to warm to this pedal however I now love it to bits.