Almost exclusively a bowline or running bowline. Almost never a carbine unless it's a small tree maybe.
I second that. From the sounds of your needs, straps are a great way to go. A 15' tow strap with a 10,000 lb capacity will cost you 25 bucks or so. I don't know what kinda logs you are pulling around or how long your haul line needs to be, but I when I retire one of my 1/2" 16 strand climbing lines I cut it out to various lengths and use it pull some pretty sizable logs around. A rope will come in handy if you need to redirect your pull line thus making it my favorite means of pulling, even over choker chains. I usually tie off a hook on one end of my ropes to use it for choking and then tie a series of double bowlines at various intervals in the rope for quick rehooking at any desired length (goes right over a ball or onto a pintle hitch slick as ****) . I have a bag full of "red is dead ropes" that i retired from anything other than hauling on the ground cuz when one breaks, oh well, toss it out and use another. It really depends how much weight you are hauling. Unless you are doing heavy logging with your pickup truck (don't laugh I've had to do it), you may be surprised how well 1/2 climbing rope will take care of your needs. If you don't mind splurging gets some Amsteel Blue.
) I'll either use a 14' 1/4" chocker (cable type from Baileys) or a chain (5/16") choker I made up that works great for small logs to 24" or so. I use 3/4" shackles to join stuff together. Chain will handle the abuse of dragging down a dirt road a lot better than any rope, cable or strap, period. 
pics? sounds like a great idea
I don't think he is saying that he can't pull trees over with any of these ropes, he is just saying that the sole reason for needing the rope is for pulling trees on the ground, because he doesn't feel comfortable enough to be felling trees using ropes. He probably doesn't climb, therefore he is unable to set a rope in tree efficiently. That was my take on his original post.
