Alot of the stability of the tripod, has to do with the head you use, for my 600 f/4 on a bogen 3021, I use a wimberley head and have never had any stability problems at all and no fear to tipping it over, for a 35mm system the 3001, 3021 and many of the lighter Gitzos work just fine, the 3001 is less than $100.00 here in the US and I use one for my backpacking set up with good success up to about 400mm, but again, you have to make sure you have a good head that helps ad to the stability of the tripod.

As Dan said, try to visit a local shop and play with as many different tripods as you can, I have found that tripod choice is often one of the most personal items we use, my wife has her favorites and I have mine and we don't use each others tripods..

Dave