I just use Prolink dry lube now. I am a bit over the top with it, but chains and cassettes last a very long time with this routine and you bike stays very clean.
Prolink is self cleaning. You need to have a completely clean chain to start off with - getting it right from the start is important. I use a removable joining link on a shimano chain, take it of and put it in a bottle I have with some mineral turpentine, then let it sit for a while and shake it. I take the cassette of and do that with turps as well. Once out of the turps I clean with hot soapy water.
Back on the bike, and a drop of prolink on each roller, and then turn the pedals backwards foe a minute and then a quick wipe over with a paper kitchen towel, then let it sit. Before my next ride I wipe it over again, and when I get home follow the same process. Now it is set up.
I then follow Bustedknuckles advice and add lube when it needs it, but I wipe the chain over after every ride. I use long thin bit of rag to clean in between my sprockets on the cassette, and clean my bike properly once a week, where I have a car wash type glove that I use, but I also clean the chain and cassette thoroughly - the prolink is not a oil based lube so warm soapy water works well, and by rinsing with clean water and drying off you are good to go for a reapplication after washing and wipe over before next ride.
I give my bike a wash anytime I have had a wet ride, and don't like using any solvent on the bike, and the above method is super clean which is what you want. As people have mentioned, it is dirt and grime which wears things out and heavily applied wet lube is a magnet for this. Prolink is good as you can also use it for brake pivots and the like - its clean and does not leave a sticky residue.
It requires more care and a routine but you get the benefit from it. I also have a spray bottle with some truck wash in it, some automotive wipes and paper towel ready to go after a ride. I will generally give the whole bike a wipe down and then toss the dirty towels, so that I have gotten sweat and any grime of. Its a good chance to check things like tyres etc. Your bikes life increases a lot with all the above, but it adds a few minutes to your pre and post ride routine.