Try something like 0/10/0/30/30 (or 0/15/0/25/30) water magic just has a lot more useful traits than fire and the 25 point is a nice damage boost, taking 30 in Arcana is pretty much a given for any build, the cooldown on attunements is amazing and the spell on dodge trait is still really really good.
As far as items, I'm not sure what is best, probably PVT or H P T armor with berserker trinkets is fine.
The 0/10/0/30/30 is what I run in sPvP and WvW and I actually do more damage than when I ran 10 in Fire. After the Evasive Arcana nerf I messed around with dropping Arcana to 20, but as Mitch says having 30 seems a necessity. You will probably notice an increase in damage by speccing higher into Water oddly enough, as one of our most powerful passive traits for damage is Water 25, Bountiful Power. With 30 in Arcane, you will have great boon duration, and even moreso if you rune for it in WvW. Each boon you stack is +2% damage, so you will easily see a boost of about 10%. Also, when I feel pretty safe, I often take Vital Striking in Water as well.
I switch around my Water/Arcane traits pretty often. With essentially all D/D builds you will want Zephyr's Boon glued to your traits, especially with increased boon duration. You'll have nearly perma-fury, which will make up for any lost precision from not speccing highly into Air.
As far as gear, I'm still in the process of coming up with an ideal pairing to what I run in PvP, but I use a mixture of Knight's and P/V/T for WvW with nearly all Berserker Trinkets except one that is Valkyrie for added Vitality. I'm still experimenting with blending a good mix.
Edit- As for weapons/runes, I run Battle/Force. I sometimes run Energy/Force, but if I'm running Renewing Stamina I notice I have constant vigor, so with wise dodging you can run Battle/Force for an increase in damage. For WvW I tend to use boon duration runes such as Water and Fire/Strength. I'm lazy and don't like dungeons so I don't have Monk runes, but those would be even better. (Sup.Water, Sup. Monk, Maj. Water).
Don't mean to spam you with a giant wall of text, but one thing to note is that in WvW if you need to swtich to staff with a 0/10/0/30/30 you can easily re-trait on the spot without having to change much. I switch from Zephyr's Boon to Quick Glyphs and then switch an arcane trait to Blasting Staff.
Edited by Ashin Dreidon, 17 February 2013 - 01:04 AM.