Given the gear you have, it seems you're reasonably able upgrade when something really nice comes along. So if you really want it, I'd go for it. We can spend our whole lives waiting for the next great thing, which is always right around the corner, and is usually great, but not usually all that much better than what we can get, and USE, now. Or, you could get the Nex with the 16 (24 equivalent) - not a GREAT lens, but not as bad as its reputation, and then you could get the 24 f1.8 when it comes available soon. If I had any appetite for their lenses I'd be all over Nex right now - they're doing some really cool stuff with their bodies and the lenses will probably be very good in time, but its pretty clear they won't be small enough for me to want to go that way. If that doesn't scare you off, I'd check 'em out. If it does, get the 28 - Ricoh doesn't seem to be in any hurry to release more GXR primes... And none of us really have any idea what the Fuji ILC is gonna look like or what it'll do or what lenses they're gonna make available for it. I'd go for it and then, if the Fuji stuff is worth upgrading to, you should be able to do pretty well selling the Ricoh gear. Or just wait a month - Fuji has said they'll be announcing something in January, so maybe that'll be soon enough to decide???
-Ray