If you want a bike that needs almost no tweaking, first, get at least a internally geared hub. I personally recommend SRAM as my top choice. I have (or had) many of them, and to me they are my favorite. I especially recommend the iBrake on their model. You fix both the maintenance and the tweaking issues at once. No rim degradation, not prone to being hit like a disc brake and good rain performance. My roommate has the SRAM S7 with the ibrake that I mounted for him. Impressive! It hasn't went through a whole winter yet so I can't say about its water-proofness and resistance to corrosion.

Fenders (especially those made of steel or aluminum), chain guard (hard to find) are also a good idea.

You should of course have it maintained (or maintain it yourself) once a year, but two is better if you ride where there is snow (once after winter, and once before). Most importantly, do your maintenance after winter, since it's the season during which your bike will get beaten most.

Alu over steel for your frame is a good idea. But if you're like me and you think nothing rides like steel, rustproof your frame. Gotta make some compromises.