Goat if you are fit and don't have a gut, then I'd say go with Small. It fits perfectly around my 31" waist, with a bit of clinch adjustment. Other than the extra room you need around the abdomen to fit your mitts through side pockets, there is no "paunch" as you call it. I am 5'9, with normal length arms, and the sleeves run about down to my knuckles if i pull them straight down, and they stay right at the wrists when reaching up. It depends how wide your shoulders are, because I'm pretty slim. I also wear small in North face/patagonia, and medium in MHW. Hope this helps bro.

Esoteric...when you say it fits like a glove, how does it fit around the abdomen and how is the sleeve length??

Hey Goat, this thing fits like a glove. maybe room for a thermal base layer, but thats about it. But I intended to wear this glued to my body, so your call. As for length, its plenty long enough. Awesome jacket, mine is in black, so can't help you with color.

Thanks Esoteric...that would be awesome. Also, let me know what color you got. I went with the Cobalt but the Everglade looks nice but I can't tell if its bright mustard color or more of a bright, yellow green color.

Goat, I just ordered this in Small, I have your exact measurements. I usually fall right in between small and medium, so I feel your pain. I'll let you know how it fits when it arrives next week, maybe save you some hassle.

The only thing I'd be concerned about is the sleeve length. If the medium is just right when you raise your arms than I'd be worried about the extra inch you'd lose by going with a small. I have to draw the waste in a bit too with my large.