KillerB6 listed some top notch stuff, but if you have a budget that isn't that high.
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Look around at some surplus stuff, I ended up building my own 'battle belt' using a surplus British PLCE belt, with suspenders and a bunch of pouches that came with it (for cheap, like $45ish) then added a few more modern attachments for it.
So don't be afraid to look at surplus kits: mollee mag, IFAK, and general purpose pouches can be found for cheap.
I wouldn't run out and buy some $70 medical pouch, and then have to go out and spend another $100 to get decent medical supplies to stuff into it...
Now when it comes to quick grab pistol mags, I like the Blackhawk 'double stack mag case' type holders. You may have to buy mollee attachments to mount these on a mollee system, otherwise they tend to go on just about any size belt you may use.
I also have their SERPA holster, yes I know its reputation and how some dummies (Tex Grebner or whatever) shot himself using one. But this wasn't caused by a flaw in the holster.
Now for quick access to rifle mags, I use a double-taco pouch from HSGI. Honestly, these double-tacos aren't that great. I would recommend getting single tacos in whatever amount you'll want/need to mount to this belt. The double ones are just a bit awkward (but still can work if that's what you go with).
So all in all I have a 'full battle belt' system for a cost of something like (assuming you buy new) $150ish. Granted mine is a mix of 'top notch' and 'surplus' gear, not to mention I bought a bunch of double tacos years ago (ended up selling all but 1 of them). So they are probably a little cheaper now (or maybe not)...
Also a note for surplus stuff, ACU colored gear tends to be widely available. No, I don't like ACU pattern either, but, you can buy some RIT dye for cheap and change the bright snow/sage-brush camo into something better suited for your needs..