My raiding main (mage) is a chanter/tailor, tho if I were to level her now I'd do chanting/JC. That's probably the overall best combo for self buffs and general utility, and they're both great for making stuff to auction.

I always take gathering skills on slave toons -- they aren't really all that useful in an instance/raid if you're not multiboxing, and I find enough mining/herb nodes without having the scanner on my main (though I'm sure I miss them when flying around).