On my first 245 (an '88), I used 195/70-14, then 195/75-14, and ended up with 205/70-14 for at least 100K miles. The latter are just a touch wide for the stock 5.5" wide wheels, but I drive pretty aggressively and I never felt it was too much tire or rolled too much for the car. I also kept them pumped up to 36 psi.

Over the 250K miles before the car was retired due to being hit, I ran the stock Michelins, Continentals, Toyos, and Yokohamas. By far the best were the Yokos - the Avid T4 in particular. Good life, good traction and wet handling, and decent steering feedback. The worst were the Michelins (too hard a compound, trading poor traction and handling for good wear) and the Toyos (way too slippery in the wet).

The 195/75-14 has the least speedo error and actually has an improved load range (92) over the stock tire (90). The 205/70-14, as you pointed out, is slightly smaller in diameter which results in a trivial 1% speedo error, and has a load range of 93.

"All weather" tires is a marketing myth, and if you need to travel in snow frequently, bite the bullet and get dedicated snow tires. The M+S rating is based solely on rubber-to-groove area and has no actual performance definition; tires intended for ice + snow have the little mountain peak icons on them and must meet winter performance requirements. Doesn't sound like you need those, though.
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