looking for a UL shirt

As I first read this, I assumed you were looking for something like a stretch base layer. Why not go the base layer route and then supplement that with a trim fit runners wind shell?

And that assumes it is for backcountry wear— or are you looking for something more travel oriented?

"any other ideas? athletic fit is a must"

While you're looking at Arcteryx, you might take a look at the Motus and Accelerator LS T's. Motus is lighter, SPF 25, breathes extremely well, and dries quickly. It's a great Sierra backcountry shirt, and also presentable enough for casual wear in town.

The Golite Wildwood Trail Running Shirt is 3.4oz in a Mens Medium.

Any number of lightweight wicking shirts will do, so I'll make your life more difficult and add another option to the pot.

I was recently given the Mountain Hardwear Way2Cool tshirt from a friend and ran a really long run in this shirt this past Saturday with a nice mix of heat and cool weather. Perfect conditions for testing a lightweight active shirt. I was very impressed with the shirt and how it worked during our outing. The shirt uses MHW's new fabric called the "CoolQ Zero". I don't know what all went into the design of the shirt, but I do know that it wicks moisture admirably and the fit is very much athletic without being too "techy". The colors come in obnoxious orange, belligerent blue, or wanker white. I would say it's most comparable to Patagonia's Capilene 1, but this shirt feels cooler to the touch and doesn't get as warm in the sun as Capilene 1 has for me in the past.

+1 on the Golite Wildwood trail running shirt. Excellent stretch, incredible breathability.

though all the running and hiking base layers look good (for a BL I just use my STP redram SS wool v-necks ..cheap!)

travel-oriented is more of what i am looking for, something with a collar that could pass as a regular shirt.

I own a couple of way2 cool t's and just (yesterday) ordered another-I'm using them for warm weather running and not another shirt in my quiver (and a have a few) wicks as well or feels as cool- they machine wash/dry up great; it's a very good t-shirt for warm weather aerobic activities

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http://www.basspro.com/The-North-Face-Horizon-Peak-Woven-Shirts-for-Men-Short-Sleeve/product/12111305574441/

Look at outdoorsy retailers like basspro and cabellas. Usually they'll have something applicable in an outdated color on clearance.