Since shaman mechanics are in flux (I haven't had a chance to play with Windfury vs Flametongue to see how the changes have affected the optimum setup, since I've been resto since the patch and am unable to pick an offspec - accursed indecisiveness) I'm going to include some fast maces and daggers here even though I'm under the assumption that in 3.1 slow/slow works fine for WF/FT. There's also Frozen Power and the rise of WF/FB for some shamans to consider. If I were a dedicated Enhancement right now, I'd consider dual speccing to get Frozen Power and seeing if the Frostbrand effect still increased my damage against mobs not slowed by it.
Ulduar 10 drops
Kinetic Ripper - The Kinetic Ripper has good stats and DPS (just behind Kel'Thuzad 25 and superior to anything that drops in Naxx 10) but with the changes to Flametongue to normalize how the proc interacts with weapon speed, I don't think a 1.5 speed fist weapon is going to be ideal for enhancement. Still, if you're using a Pride in your offhand, the 20 DPS and nice stats might be enough to make you consider switching to this. And while I'm fairly sure that slow/slow should be fine for DPS the enhancement shaman in my horde raids swears by fast offhands even after 3.1, and until I get a chance to really play with the spec I can't contradict him from expertience. (Maybe once we have everything on farm.)
Plasma Foil - well, it's got spirit instead of MP5, but with the crit and spell power I'm pretty sure we're looking at a weapon for healers here. It's inferior to the Torch of Holy Fire from 25 man Naxx, but consider that it's a drop in Ulduar 10, it's pretty much superior to any other healing option besides the Torch for a shaman. Although I have to admit I'd almost rather have the crit and haste from the Blade of Dormant Memories than the spirit from Plasma Foil. This leads us to our next dagger, actually.
Stormtip - I'm not terribly knocked out by the 10 man dagger options I'm finding thus far. This has haste and spell power, yes, but also spirit and no hit to speak of, making it a decent healing/DPS option if you don't have better, but not exceptional for a shaman.
Pulse Baton - This is a solid weapon for a restoration shaman. We could debate for the next six months which is better, this or the Hammer of the Astral Plane from 10 man KT (I would actually prefer the Pulse Baton for a resto shaman, but I could be swayed to the side of the Hammer for an elemental shaman) - even lacking the haste and with the MP5, it's got a solid amount of spell power so if you're a 10 man raider this is certainly one of the best options for you. If you also raid 25 man, I'm pretty sure the Torch of Holy Fire beats this. Still, if you don't have that yet, here you go.
Unravelling Reach - most caster shamans prefer a main hand and shield for the higher total spell power, but this staff has a huge dose of hit, high int and reasonably high spell power (not as high as I would like, and probably likely to be overwhelmed fairly easily by caster MH/Shield combinations) - the down sides are the spirit, which is a better caster stat for druids and mages (and priests for all I know) than elemental shamans.
Pillar of Fortitude - your trash drop healer staff version of Unravelling Reach. It's got a decent amount of crit on it (so it's not useless to elemental either) but in general doesn't scream 'shaman' to me. Still, some of us like staves.
Bloodcrush Cudgel - The speed isn't ideal on this trash drop from Ulduar 10, but the stats (especially the expertise) might be useful if you're not capped in any of them yet. Worth taking if it's going to be DE'd anyway, you happen to be low on expertise or your offhand is 20 dps below it, as per Kinetic Ripper above. If you're confined to 10 man raiding, however, the next item is going to be BiS for enhanceent shamans, especially orcs.
Touch of Madness - DPS axe! 2.6 speed! Hit, crit, AP and agi! Orc shamans, I think we may have found a weapons for you, finally. The bad news is, you'll have to kill Yogg-Saron in 10 man to get it. The good news? It's not a hard mode drop, it's not unique. At only iLevel 219, it's not better than Kel'Thuzad 25 drops (iLevel 226) like Calamity's Grasp but if you're an orc that axe racial will give you much needed expertise, and if you're just raiding 10 mans or haven't gotten the fist from KT to drop then get ready to hack at a gigantic brain until he drops this axe for no raisin. (10 points if you get that.)
The Masticator - Looks like Kinetic Ripper, but is a main hand fist with a much better speed for a shaman, drops from the Iron Council on hard mode. I'd rank it as superior to Calamity's Grasp, although both are iLevel 226, due to its slower speed and gem socket, but it's very close.
Ulduar 25 drops
Golden Saronite Dragon - this is a drop off of Flame Leviathan in Ulduar 25. It's also a hard mode drop, which explains why it's 10 DPS above similar weapons that drop in Ulduar 25. It's best in slot for an enhancement shaman due to its speed, stats, gem slot and raw DPS, but it's likely you'll be a ways off from getting it as it will take completing the Leviathan on hard mode (and since there are four stages to hard mode Leviathan depending on how many towers you leave up, that could be a while).
Insanity's Grip - This drops from the Cache of Invention after defeating 25 man Mimiron. Until Flame Leviathan goes down on Hard, this will probably be the prefered main hand for enhancement shamans (orcs might prefer Touch of Madness although 15 DPS and overall better stats seems likely to overwhelm the orc racial, especially when this has expertise rating on it).
Vulmir, the Northern Tempest - one of the few new slow weapons that can be offhanded by an enhancement shaman, you may well end up seeing lots of shamans dual wielding a pair of these. Competitive in damage and speed with Insanity's Grip, it would really come down to availability and other gear options. I really like this weapon's itemization, it's nearly perfect. Agi for AP and crit, expertise, hit and more AP.
Soulscribe - This, to my eyes, is much better Elemental itemization. It drops from 25 man Yogg-Saron and has haste, crit, and higher spell power than even the Torch. Certainly not a bad option for resto either, but I'm thinking they'll be looking more at the next item.
Guiding Star - the Resto choice mainly due to its MP5 (I could see elemental taking it if Soulscribe hasn't dropped yet, or resto going for Soulscribe for the crit) - the difference here besides the MP5 is that Razorscale is a lot easier to get to than Yoggy.
I'd hoped to cover offhands and shields in this post as well, but that will have to wait until next week. I also expect to have to come back and cover items that hadn't been discovered yet (or which I simply missed) - such are the perils of talking about new content.