Andy,
I'm also a newbie to UL gear, about a year using it. Based on that I can say pj & others here at BPL are excellent sources of advice and info — IMO best single source on the Internet.
I also highly recommend reading the gear reviews, techniques and features articles here at BPL.
That said, pj, Dondo and others are right on as per always.
So, as one newbie to another: I highly recommend checking out the Henry Shires Tarptents' Squall 2 and the Gossamer Gear Henry Shire's design Squall Classic 2 person tents. Websites at:
http://www.tarptent.com/
http://www.gossamergear.com/
GG-HS Squall Classic:

After checking around this is the first UL tent for me. It is not as light as a tarp, but pretty close.
It weighs right around 1 1/2 pounds with stakes, rear curved pole, front pole, and floor, w/ stuff sack.
It holds two comfortably enough and with gear stuffed in to be validly called a 2 person tent, which is why I bought it for my partner and I. I absolutely love it.
It ventilates without any issue, and the sides can be staked down to cut down on flow through the side mesh.
It is sturdy, durable, but you need to treat all UL gear with care IMO. It also packs well if you take it out of the stuff sack, shove it in the bottom of your pack on top of your ground cloth, for protection. The poles fit standing upright in the pack, I put them next to the side near by back.
Notes on HS Tarptent Squall 2:

Specs at: http://www.tarptent.com/tt2specs.html
The Squall 2 has more headroom than the Squall Classic, note the spreader piece holding the front top spread out. Also, two front poles is supposed to add more stability.
The fabric from which it is made is a softer, heavier fabric than the fabric in the Squall Classic (if it is like the fabric in the Tarptent Rainshadow 2), but there is a weight penalty of several ounces over the Squall Classic.
So from one newbie to another, hope this was helpful .. take it for what it is worth, from a newbie … but I thought I would take the time to fill in some newbie gaps after pj'Dondo/et al. gave you such good advice re: check out the Tarptents. (I have no experience with SMD, but they are also supposed to be good).