Depends entirely what effects you want I guess. I only use my digital FX unit for reverb and delay, therefore I use a g-major set to killdry in the parallel loop, therefore I get no tone sucking at all of any kind. Then for chorus, etc. I use analogue stomp boxes in front of the herbert. Unfortunately you then have to do more stomping, and now I want a VHT valvulator so I don't get tonal loss running through long wires and true bypass pedals, but as soon as I use a wah I have this problem with long wires anyway! If I'm just using delay and reverb then I can ditch all the stuff in front which makes things easier. Running long cables in front of the amp, no matter how expensive, will lose tone without some kind of buffer.
If you want a unit you can do all effects with, then it depends entirely how much you want to spend, I just figure there's no point in spending loads if you don't really have the money and are using it in the parallel loop...
