New 40K League: What's Next?

I didn't know Tyranids could swim!

Over at Gaming Underground, I've been through two 40K leagues this past year.  In the first I built up the Space Sharks; in the second I played the Merkan 76th Imperial Guard, adding a few units over the course of the league.  Soon we'll be starting a new escalation league up, and I'm unsure of what to bring.  So I thought I would solicit some feedback and see what readers/other league participants might want to see in reports/on the table.

The contenders:

The Space Sharks!  Vanilla Space Marines.  I might add a few units or figures over the league.  As is they're not terribly well suited for 6th edition - very limited options vs. flyers in general and unit-erasers like Heldrakes in particular, and all those power fist sgts. tend to do poorly in challenges.  They're fun and I always enjoy seeing them on the table, and they're still pretty fresh.

The Scythiak Usurpation!  Old favorites here at the blog, the IG-rules using Chaos-worshiping techno-barbarians, cultists, and assorted ne'er do wells.  While I just got done playing an IG army in the last league, I could probably do these differently enough not to be a repeat.  Depending on the league rules, I may not be able to do things like the big Ogryn mob (too many points in one force org slot), and would likely add a few units/vehicles over the course of the league.

Kommissar Krumpa's Blood Axes!  I have a dakkajet for them that would almost certainly get done over the course of the league (it might anyways, regardless of who I play!), and I might add some other units and upgrades too, like a deffrolla for the wagon, some non-mega nobs, maybe even something like flash gits (though I could just use the tinboys) or lootas.

Merkan 76th Imperial Guard!  Currently I'm not too keen on playing the same army again, and I've already added a few things to them, but I could potentially be convinced.  In general though I think they've earned a break.

The Endless Ones!  Chaos Space Marines.  I would probably add a few things to them over the course of the league (at least get a few extra spawn/DP done, maybe a few other auxiliary units), and some of the Hell Hounds might feature if I needed extra bodies fast, or didn't want to duplicate something like a Vindicator.

Eldar Corsairs! These would require the most work to get started, and with starting a new job soon I'm not sure I'd have the time, but I could at least get stuff assembled and suffer self-loathing while I played unpainted guys for a while until I could go back and paint.  I'm not even set on lists or even color schemes at this point.  It would be a mostly Codex: Eldar army (as I want Eldar Heavy Support, like D-cannons, warwalkers, wraithlord) with some Dark Eldar allies (probably mostly Kabalite Warriors and a Razorwing).  They would be entirely new, which would be good in a freshness sense, but could be bad as I fumble my way through them.

So dear readers and other participants, your thoughts?