Professions

Thinking of leveling my DK to 85 (is at 81 now). Priest is my main. Mostly 5 man content with both toons, as my schedule makes raiding difficult.

I have mining and skinning at 450. I know this isn't ideal in terms of bonuses/perks, I just want to know how gimped it will make me. Should I switch out either or both professions? For what? Thinking mining is okay, and a nice fit with jewel crafting maybe?
Since all you do is 5 man content, it really doesn't matter what your Dk's professions are. If you were to raid with your DK, then it would be ideal to pick up professions like jewel crafting or blacksmithing. Sure with your current two prof's you won't get anything to contribute to your dps and if it really matters to you, then picking up jewel crafting would give you a nice extra 81 strength. But if you plan to mine and skin frequently with your DK to make money, then keep the two professions.
For end game stuff like RBG/Raiding, Id go with Jewel crafting and Black smithing, simply because it will grant you a grand total of 161 extra strength, However if its just 5 mans and the occasional raid when schedule is not busy, Go with something fun and something profitable (Herbing should be okay since it does a haste buff).