Argus is definitely one of my favourite albums in every aspect, but particularly Martin's incredible Thunderbird tone and playing - Sometime World should be far more well known than it is, such a fantastic bassline.
WIshbone Four has some great basslines and tones, particularly the aforementioned Sorrel, but ropey production and slightly lacklustre songs let it down.
"Interesting" fact - MArtin's tone is the sound of the Thunderbird neck pickup only, sent theough two amps - one clean and bassy, one toppy and driven. I recently saw MT's Wishbone Ash and these days he's using a Hartke head for the clean lows and an Ashdown ABM for drive, all through Ashdown MAG cabs. He also had a Blackstar pedal for boost when soloing - sadly he buggered up the solo to Why Don't We, and looked rather annoyed with himself. Soundwise, it was his classic tone through and through.