Well, a combo is fine for my purposes. If I went for a head, I'd be compromising on a cab to stay on budget (which could be done, I've seen used 5150 cabs go under $300 for instance). Price is a significant factor. If for instance one was to say a Mark IV would be ideal but a <whatever> is $400 less and gets you close enough, I'd seriously consider <whatever>. I'm absolutely not interested in a rack system. The separate EQs is a big deal, but not worth more than perhaps $300 to me.
Maybe you can help me rule out some of my options. Why should I avoid the F50, DC-5, or Express 5:50? I'm not saying I have any preference either way about them, only that nobody has commented on them. The only comments have been about the Marks. Is there something about them that doesn't fit my stated purposes, etc? I think I can probably take the Express off the list since its right in the same price range of the Marks, but the 5 watt mode is nice. I'm curious as to opinions on the F50 and DC-5 though.