I wear PI Lobster Claws with liners for temps under 20, without liners for temps under 35. I also have a pair of mid-weight gloves from Avenir for temps between 35-45ish and another pair of heavy gloves from Canari for 40-55ish. The Canaris aren't as heavy as the Avenirs but they're heavier than the usual long-fingered cycling gloves. I hated the Lobster Claws last year - they felt awkward but this year I don't seem to have any issues and man do they keep my hands warm. I've worn them down to 0 with liners without any problems.

and we don't have salt/slush issues here so I can't help you with that one - but I'll bet Denise can!