It's all very well saying you get full control doing it yourself but it's knowledge I don't posses, and would only wreck things doing it myself...
I dev B&W at home and send off C41 and E6. However, I am rapidly going off colour film photography and once my current stock runs out will just do B&W. I like to complete the process myself and it also means that if it goes wrong then I only have myself to blame!
I generally develop my own (apart from slide film - I've got a few rolls of prepaid sensia left) but I'll reconsider developing c41 myself the next time I run out of chemicals.
C41 processing is a bit uneventful, there's no real scope for experimentation and it's a bind to maintain the temperature and times - a machine can do it so much better.
B&W developing allows for more choice and variation and you can 'develop' your understanding of photography at the same time.
C41, on the other hand, is good for starting out. The kits come with precise instructions on what to do and have enough of each of the chemicals to develop 15-20 rolls. All you need to do is follow the instructions.
On the other hand, E6 processing is similar to C41, maybe a little more involved (an extra tankful of chemicals say), and can be a complete pain in the backside to scan afterwards. But it's all worth it - every little bit of hassle, to see a roll of perfectly formed, full colour miniature stained glass windows emerge from the tank of noxious chemicals...
What do people who are developing C41 and E6 use to keep the chemicals at the right temps? And do you just keep taking the dev tank in and out of any water baths for agitation?

A big sink full of water at 39 degrees and a kettle of recently boiled water to splash in there if the thermometer drops more than a point or two..
I'd like to develop B&W myself but the combination of time and available space means it's unlikely for now so they get sent off. I try to avoid high-street development unless it's a test roll that I want a quick turnaround on as I've had some poor results previously......[snip]...............

Ahh, good stuff! Thanks!
So is it just the developing that's temperature critical or are any of the subsequent stages as bad?
Dev my own B&W, i think if (when?) i try some colour films i'll probably take them to somewhere for the first few goes, then soup them myself when i have enough money to get all the kit i need.
There's really not much more kit needed - a few more bottles to hold the mixed up colour chemicals, and maybe a couple of extra measuring jugs. As long as you've already got a decent thermometer, then it's all pretty much the same kit!
Hardest bit of colour processing, is being absoloutely rigorous with the timings, especially as the tetenal chemicals have a bit of a sliding time-scale - the blix takes 4 minutes for the first film, but can be upwards of 15 minutes by film 13. I plotted the times on a bit of graph paper, completed the curve, and used that to interpolate the times for each individual film - them it's just a matter of keeping a tally of how many films have gone through a particular set of chemicals. It's not rocket science, it's just being methodical, but it's the best way of ensuring a consistent colour balance. It's not as much fun as black and white, where experimentation is a bit easier, but, certainly in the case of E6 processing, the joy of seeing your slides emerge fully formed from the soup outweighs the other considerations.
So, what's the best way to go? And please put your motivation as well - e.g. you're not satisfied with quality, too expencive etc!