TBH IMO I think your best bet is the E7 over the Lumia 800.
Despite the Lumia 800 still being available for sale on the high street, it won't be long before it's dead and buried by Nokia and you'll feel shafted all over again.
The E7 still has that gadget appeal, so if you decide to, it's easier to sell on for another N900/N9.

I have looked and looked and looked and there's nothing out there that screams "Buy me.....buy me" so I'm sticking with my N900 for a bit longer. I'm not interested in all this dual-core this and quad-core that crap, I just want an efficient OS and a decent hardware feature list on a mobile device and the N900 delivers (and in your case, the E7 would too) and I'm not really expecting the first Jollas to tempt me in that respect either.