I know how appealing guitars are. As much as I love keyboards, the sound and feel of electric or acoustic guitar can't be beat. I play bass as well and recently picked up an Ibanez 5-string with active electronics plus a Fender Jazz Bass Special fretless which has had me slapping and plucking again lately.

As for Takamine and Martin guitars in the $500-$700 price range I'd definately recommend looking at Takamine. You'll get a great Takamine in that price range but the cheap Martins I've seen really aren't worth looking and don't compare. Maybe Martin have changed their product line and someone will prove me wrong. But all I know is I tried some cheap Martins and ended up buying a Takamine instead.