Tarp camping

I'm researching tarps and I'd just like to get some advice or suggestions on the subject. The kind/type of ground cloth is the main thing I'm concerned about. Should I have a bivy with a ground cloth? I really don't have any experience with tarps. I'll def be in areas with rain and maybe snow. Weight and compactness means a lot to me.

This is probably the best tarp I've found:

http://www.gossamergear.com/cgi-bin/gossamergear/SilTwinn.html

The best tarp in what respect? Just curious, I knew someone who has one they're thinking of shelving in favor of a tarptent.

I've looked a lot at bivies and tarps - some of the bivies are heavier than tarptents. There are a ton of options and some don't absolutely require a ground cloth. A bullet proof (heavy) bivy probably wouldn't really need one.

Gossamer Gear, while you're there, has polycro ground sheets. I've used a trash bag before. One of those cheap 2 oz plastic rain ponchos would be a dual use item - ponchos being what they are, even if it has a few holes it will still keep most of the water off you in the rain unless it's really pouring, which is when you should have real rain gear anyway... 2 mm painter's drop cloth is what I've made ground sheets for tents out of before, a couple bucks and you have a whole bunch of them for the trouble of cutting them out.

For snow you might look at mid tents instead - Oware has mids, Black Diamond too. Use with or without bugnet. Very good in snow, I hear.

I have two large tarps but I usually hang my hammock under them. I've pitched one on the ground in several occasions, however. It's caternary cut so shed the wind like a champ. If you anticipate being in a lot of precipitation you might think about where you're going to cook while it's raining or blustery and whether the shelter you choose has room for that - I've had pretty good luck under an open ended tarp with the closed end into the wind.

I have been using a Granit Gear White Lightening for a year now. I used it for 9 nights in Grand Canyon. It is a little heavier 8 x 10 19oz because it has adjustable straps at all the tie-out points and a sewn-in stuff sack. What I like about it is the edges and ridgeline have tension tape (stretchy) and it stays tight. I also use it for one of my hammocks and slept under it in a monsoon last fall.

You can use a piece of tyvek for a ground cloth or a scrap piece of sil. I have a bug bivy if I need it or I can use my hammock and bug netting for a bivy.

There are several cottage industry guys that will build anything you want at a very reasonable (cheap) price. Jacks or Better, Backwoods Daydreamer, Warbonnet Outdoors, Speer, and OES to name a few.

These guys all do great work and have a good reputatution, not to mention the fact that you will deal 1-on-1 with them.

I don't know about best but I just ordered an MLD trailstar and am really looking forward to using it. From everything Ive read and seeing all the different pitching options is looks like a great tarp.