I'd love us to sign:
Yanga-Mbiwa. Djourou's a decent 4th choice on paper, but in practice he struggles badly when being thrown in after weeks without playing. Every player does to be fair, but Djourou is downright terrible when rusty. A liability. And he's not going to force his way into the team regularly because he's just not good enough. Yanga-Mbiwa is in a different class and he can be signed to a pre-contract in January. At the very least he'd give us better depth in the position than Djourou does, but I reckon he'd become a key man for us in time.
Yann M'Vila. I know all about the troubles he's had this season, but he's a quality footballer. He'd give us something we're lacking in midfield, and he'd come cheap. Wenger would sort whatever problems he has out and we'd end up with a really good player. Give up on Diaby, Arsene.
Sign Theo or sign a top attacker. If Walcott leaves, and I think he's almost certain to, then we're left with Chamberlain, Gervinho, Arshavin, Podolski, Giroud and Chamakh as our options for the front 3. Even our tight fisted board can see that's not good enough. I think we need another top attacker regardless of whether Theo stays or goes, but there's no way we're going to get both. The calibre of player we chase will be very interesting to see.