I would get a Cosmic SLE. Solid break, aero, all terrain.
On a side note, how is Mavic hub? Compared to say Dura-ace, Easton or other brands? I read some old forum topic that has nothing positive to say about Mavic's hub quality in general. Looking to buy the SLE, though not sure yet.
Yeah - I guess this is the stuff that bugs me. Apologies for picking out this response in particular ichobi (as there are obviously plenty of very similar posts in this thread alone), but are the opinions you've offered backed up by anything, other then perhaps an experience of "I've been happy with this wheel, though it's perhaps one of only two or three high-end wheel I've ridden".
Solid braking - yes, it's not carbon so that's a bonus (but one taken against rotating weight of an all carbon rim I suppose)
Aero - no. Unless you were referring to using this wheel with a 20mm tire, please don't assume that depth = aero. It doesn't.
All-terrain - why? technically you could use any wheel anywhere, but that doesn't mean that it's suited for it. Using a Cosmic in the mountains surely isn't ideal versus a lighter-rimmed wheel that would brake and turn much more easily. This seems like saying a touring bike is all-terrain.
Okay, sorry for the rant, but I hope at least some of you can appreciate where I'm coming from.
As for the hubs, Mavic made the switch ages ago to a free-hub bushing instead of a bearing - a move that saved 15g of non-rotational weight. The experience seems to be that if the wheel is ridden in a wet climate (UK in my experience), it holds up reasonably well without requiring excessive service. If it's ridden in a dry climate (South of France or Canadian Prairies in my experiences), then it will howl like a banshee within the first season if you aren't regularly taking it apart to grease the freehub. That said, this isn't a tough job, so it needn't be a deal-breaker.
In comparison to the hubs you've mentioned, Easton certainly had some reliability issues with their hubs in previous seasons, but I don't think there is a mechanic or knowledgeable rider out there who wouldn't take a DA hub over a Mavic. Dura-ace have proven to run smoother for longer - with very, very few exceptions, they are a great example of 'bombproof' parts.
The only downside for DA hubs is a slight weight increase versus the Mavic or Zipp hubs, but when you look at this in terms of complete wheel builds (which I'm assuming you are, if comparing against Mavic), it's almost a bonus. Mavic and Zipp have shed significant amounts of weight from their hubs in past, which means that for any given comparison of similarly weighted wheelsets (eg. Ksyrium vs C24 or Cosmic vs C50), the DA should always have a lighter rim and less rotational weight.