I recommend a good tuner as a must. I use the Korg DT-10, and I love it! It is the most accurate one out there, really easy to read in the dark, simple, built like a tank.
Other than than, get yourself a 2nd hand Line 6 Bass Pod Xt from ebay (bass pod live Xt is better, but more expensive). For the same cost as a few mid range pedals you get a world of sounds that are customisable from heaven to hell! I love mine to death! It is also a great recording interface.
Single pedals are 'better', but for ease, cost, and amazing tone, bass pod Xt all the way!
