Greatest cards for mining R9 270, R9 280x, R9 290, 7990, etc.

[NuSalvo]

I'm just looking for people's opinions on what the best card is and why.  I have some rigs right now, 3 are running 5 x R9 270 and one is a mix of a 270x/270/7950.  I'm looking to do two more and was considering going with R9 290's as they've come back down in price a little and are readily available.  That, and they are one of the higher-end cards, so hopefully they'll retain most of their value.

I know Gridseed has far less wattage / kw, but I'm concerned with resale value; GPU's are GPU's and have another main use besides mining while Gridseed's are used only for mining.
 I can resell GPU's later for close to what I paid, Gridseed becomes worthless when new hardware comes out.  That and I only pay like 0.06 / KW.

[roslinpl]

I am so sorry but best card for mining is this one:

I can sell you it is working :] Hashrate invincible.

Anyway IMO - this looks cool .. isnt? 7990 is very good.
http://www.youtube.com/watch?v=MIuoLd8aaas