Ha! I also started playing way back when.. I also took a decade off...I also am just now getting back into it. Welcome back, brother. Rock n' roll never forgets. Or something.
I think you'd do well with that GK head. I don't have the 200, but I own the MB500 and I'm very pleased with it. The difference between the 500 and the 200 is that I get a sweepable knob for the "Contour" (mid scooping) and you get a toggle switch. I also get the GK "G.I.V.E" circuit in a separate gain channel, ostensibly for "growl," along with footswitch to activate it. And more watts, of course.
If you think you'll never outgrow a single modest cab, I say go with it. If you suspect you might one day need a bigger rig with a second cab, you might want more watts.
With regard to cabs... I haven't tried the SWR 210, but if you have good experience with them, why not. You might also look into a 115 (or a pair of them). Also, there's a few really nice 212 cabs on the market. I have the GK Neo one--very nice indeed. Louder than a 210, smaller than a 410, excellent tone. Their 212 and 412 cabs have excellent reputations here on TB.
Finally, if you need a head and a cab and your budget is $600-$700, you should be prepared to go used, at least for the cab. I figure if you spend $250 on a new MB200, that leaves you in pretty good shape to get any cab you want as long as there's a decent used market to draw from. Heck, I picked up a GK 410 a couple of weeks ago for $199.