Jaans, A lot of what you state below is even more lade with personal bent than what Roger said. Some comments:
Learning the light is learning the light, whether the meter is in the camera or hand held. Sure, I own un-metered bodies as well as metered, but the simple fact is that metered cameras have certain advantages. You can always use a hand held meter and manually set your exposure. I personally do not feel the need for AE, but I do feel the need for an integral meter as it helps me work the way I like - a personal thing I know. I do not feel remotely disadvantaged or any less ignorant of what is going on re the light though. Why is not using an integral meter better in the long run? My exposures with an integral meter are every bit as good as I will ever need them to be, excepting the odd error, which we all make. I simply shoot my various cameras as I do and then adjust film speeds to ensure that they all give me well exposed negs. I rate my Leicas 2/3 stop slower than my Mamiya and Bronica, but the negs end up with the same exposure using their internal meters so I can work the way I like using their meters and everything runs smoothly no matter which body I use.
As for the body, most Ms feel more than smooth enough and as an owner of a M2, M3, several MPs and a M6 I personally do not think the smoothness differences are even remotely noticeable if I am actually engaged in taking interesting pictures. If it is noticeable, chances are that I am not taking a photo of anything terribly engaging! FWIW the shutter release on the M3 is smoothest, followed by the late model M6 classic, with MPs behind that. I am sure someone else with the same cameras would say differently. All are built plenty well enough.
There are some very good reasons NOT to buy M2s, M3s and some M4s - mirror failure and also prism separation. Quite a few people get stung buy these issues, which are unlikely to bite you if you go for a later model. They are not cheap to rectify and a huge ball ache.
Each to their own, but to suggest it is somehow better to guess exposure, writing notes, testing etc rather than actually measuring the light sounds like a pretty flimsy argument. Remember that you can measure the light with your integral meter and makes notes too, then when you encounter similar conditions again, at least you have a constant (another reading from the same meter). Sure, estimation worked for the greats 50 years ago but they also produced some terribly exposed negatives - speak to a master printer who have to fight their way through thin shadows and blown highlights doing archive reprints. Just look at some of the prints too, which show tell tale signs of neg underexposure. A meter gives you facts (which one must interpret) and that is an awfully good starting point for getting things right IMHO.
In my case the absence of meter/arrows/lights/electronics forced me to slow down, pay more attention to existing light conditions. Recording the light conditions on a notepad, recording exposure and testing from there in the darkroon. Granted it is a lot slower and more time consuming than metered shooting when you are starting out, but it is more beneficial in the long run.
Besides, one may wonder why this 'empty article of faith' that you allude to has only recently aroused your suspicions? For an experienced photographer with a long history in the medium, why is this such a recent revelation?
I guess one could put it down to the recent internet invasion with every photog and their opinion. I assume that scenario wasn't as evident before with only the print medium of magazines and books to communicate ideas.
Back to the topic. To the original OP, I doubt that you would regret getting a good condition M3,M2, or M4. Once you get one you will see what all the fuss is about. Get the M3 if you want to concentrate on the 50mm lens, get the M2 if you want to get the 35mm lens or get the M4 for the best of both worlds. One could argue that the camera is merely a lightbox for capturing images and the M4P would then suit your needs. However, if you want to feel and enjoy every inflection of the camera then you won't regret one of those originals. The actual act of taking the photograph is heightened. But, each to his own.
