I'm in a band that has begun gigging pretty regularly (every other weekend about) in VFW halls and American Legions.
I play out of a Peavey Valveking 100, Carvin V412t, and an Epiphone G400 SG.

To achieve the sound I wanted I use a metal muff and my head's clean channel. The gain channel just wasn't cutting it for me, it was a tad muddy.
The sound is decent, very loud; but not exactly the quality i'm looking for. We play pretty melodic hardcore.

There was a valveking head at my local guitar center so I went around plugging it into different cabs to see if there was a difference in sound and big surprise there was. I've read reviews on all my gear and it's all pretty decent. I just don't know what to upgrade. I've had the head for about a year but I bought it new so I don' t think it's the tubes. My best guess is that it's time for an upgrade to my cab. I payed about 250 for it used, and I can get that right back from a friend who wants it.

What would be a good buy for me? I played a marshall 1960 lead cab (it sounded better on just the high gain channel then when i play using my metal muff with my setup) but 700 bucks is a little pricey for me. I don't want to spend more on my cab then I did on my head. My price range is around 400-500 bucks. I can swing a little more if necessary.

Would a new guitar make a difference as well? Honestly, I've saved the money, I just don't know where it would be put to best use.

thanks in advance,