In my experience it can team amazingly well or shockingly poor. Those that can use it well can do wonders with it and can be a real asset, those that can't can quite often be a menace to a team.
It's amazing solo, though I've only played the defender (storm/ice) and controller (fire/storm) versions, but I can only imagine how good it could be on a corruptor. I had a blast for sure and it was very safe and I don't know many people who've played stormies that don't love them.
I would go with Fire or Ice.
Seconding the Fire/ or Ice/ vote.
I've got a guide for /Storm in my sig if you want to take a look. Its definitely a very unique set, but also very tricky to play well. That said, if you can play it well its monstrously powerful.
Support Guides for all Corruptor secondaries and Fortunatas
The Melee Teaming Guide for Melee Mans
The Melee Teaming Guide for Melee Mans
I have an Arch/Storm that I love. The nuke doesn't crash end so it goes very well with the toggles -- Steamy Mist is always on, and Hurricane often is. Also, I primarily lead with the storm powers (Lightning Storm, Freezing Rain, Snowstorm if you're into that kind of thing) so redraw is not a serious issue for me.
I do agree that it is a set that can be tough to play well. Hurricane tends to be the main culprit and requires some practice, but when you manage to simultaneously debuff and gather all of the robots around the computer during the ITF and then hit em with RoA you will feel like a god.
Thanks for the Guide info, Silas - nice name to it.
I was hoping the Rain/Rain combo of Fire/Storm would be toon-defining.
Freezing rain/snowstorm can just gut a good sized spawn while your team lays into it.
I've been on my Storm/Ice defender lately leveling up. Only 28 right now, but dang he is just a lot of fun. Freezing rain/ice storm then toss a snowstorm on something and hold an annoying target, spot heal as needed.
I actually need to respec at some point to drop at least one of my blasts because I just don't have enough time to use them in most fights and managing the debuffs is just more interesting anyways. A corr would probably be a bit more blasty obviously, but still have all the good fun.
I am from the perspective of a fire/storm controller (50) and Storm/Electric Defender (40).
The only power in storm that underwhelms me is Gale. Though same swear by it.
Read the guides in the controller and defender forums. They may not be spot on, the information however will still be relevant.
My Use of storm is very different (though with some overlap) on the two characters.
The controller lays in with flash fire/fire cage to lock down then follows with 'rain walks up to pbaoe range (hot feet) and while spamming fire cage for lock down each time its up lets loose with lightning storm and tornado and water spout (patron pool). With everything rooted and -KB things melt fast. I have thunder clap and cinders as back up holds, thunder clap has a wonderfully fast recharge so it is up often. With team play or when things don't go as planned the extra control I get from freezing rain, thunder clap and cinders do wonders and the stealth/defenses from steamy mist are very nice. I also have all four leadership powers. I can solo quite effectively with or with out imps out (imps do speed things up though). There are nice proc IO's for all those powers.
The defender plays very differently.
I need to make much larger changes with the defender between solo and team play. I also think the defender would play much more like the Corrupter.
With steam mist always on and hurricane mostly on, I will drop freezing rain which besides all the nifty debuffing also has a fair level of control, and then get lightning storm, voltaic sentinel, and tornado out as fast as possible. They do the bulk of my damage. I then use hurricane to frequently debuffs every mob in sight and when the topography (office, where house, etc) permits stick things in corners. I then use the blasts to plink at things as needed. I can sit at point blank range with a spawn and use Zap over and aver because nothing can hit me to interrupt it.
For team play I don't use tornado often and focus on debuffing and healing more then damaging. Lightning Storm/sentinel being fire and forget. I also hang out at the back of the party, mostly out of melee range so as to not piss off the hand-to-hand members of the group. If it comes up I will let range people and everyone know if they are on trouble to run into the hurricane for safety. On some maps like the where house ones I will as needed push spawns into the corner and keep them all nice and bunched up while pulling their teeth.
These play styles work for me, they are not the only viable ones for the ATs.
Both characters are very end heavy. I have the Alpha cardiac on the controller and some procs/io sets to help with end and he can still run out. The defender I need to be careful how much I use my blasts or I will drop my toggles though both recharge fast and putting two back up isnt to awful.
I dont use snow storm much because of end issues with my builds, though I plan to pick it up on the defender at some point. It is very good at debuffing and slowing down spawns.
Things to consider: Storm is very endurance heavy. You will need to use lots of end-redux SO/IO's. At 50 you can fix the bulk of the end issues.
Knock back can be used for effective control. Solo, or on range based teams, this can be very good. With a hand to hand based team the chaos a stormy can very easily create is usually not welcome and can generate a fair level of hostility from the other players.
Some people, who perhaps have rigid ideas on how to play the game, wont play with storm and will not invite you to groups and/or be hostile while in a group.
I have successfully tanked and been sole healer on the defender, though not ideal you _can_ do it.
Thanks Zep, very useful info. I'm pretty sure I can manage the End, and it's kind of nice for teams that you don't really want to be on anyway self-eliminate themselves. 
I rolled it up yesterday. Sweet looking toon. Fire should pretty much get me through the low lvls fast, then Storm will kick in when the enemies get more serious.
I don't see anything in the guides on Storm. How does it play as a secondary? Seems like an End Hog, lots of powers that overlap each other, and maybe not team friendly. But it's a pretty unique set of powers and hard to put my finger on. Does it team well, solo well, have good synergy with any particular primaries? Thanks!