I somewhatsecond what warrenpridgeon said. I very rarely use effects aside from volume, some noise killing for the Marshall and the occasional chorus-delay type thing for some backing chords. Since I am far from an expert or accomplished player, I've decided to keep things fairly simple (individual product wise) and went the multi-fx route for now. The Boss GT-100 was an easy choice simply for reliability history, ease of use and flexibility. And of course the fact that I don't use the amp modelling, I've heard it is not as good as the alternatives. The RC-300 is something I use pretty much everytime I pick up a guitar to play or practice or create.
The reason why I like my Boss pedals is because I don't have to think or consider them, they are just "there doing their thing"