As someone with a lv180+/TM200+ dark Witch, I have a degree of experience. :s Her elements are fire/electric tho and I'm strictly PvM.
While 1423 is good for more survival reasons, I can recommend the default build 1432 as well, especially if you're fire.
As far as other elements go, I've known people with fire/electric (myself included) and water/electric. Both combinations are excellent. Going by experience, fire/elec will have the most DoTs. It's fun to watch a weaker CT boss suffering from Hellfire, Phoenix Rising and Scorching Earth all at the same time. 8D Keep in mind I haven't tried Tesla Field as I haven't got it yet. As far as water/elec goes, well you got Shard.
Being PvM, I went with pure MA. But if you're gonna PvP/GvG and/or have the equips to make up the MA/LK, then by all means, go pure HP.
If you're gonna go pure HP, then I'd probably recommend 1423 or hell, maybe even 1441 if you're crazy enough. XDDDD
Hopefully what I said helped and good luck~
EDIT: Rawr, Snowberry ninja'd me!