A grimlock re-release is coming (not saying it will be cheap though).
If your Starscream is not MP-11 a re-release is just out for him also (imo, worth the upgrade).
Sideswipe may be getting another run too (there are heaps of KOs of this mold out there, that is what you see cheap).

Soundblaster, G2 Sideswipe and Wheeljack preorders exist so if they interest you also put money aside for them. UltraMagnus, Bumblebee and more are also heavily rumoured for 2014 also so again, don't leave yourself short.

MP-01/2/4 I would only consider buying if i were a completionist, or would never sell Megatron if a new version can out, or viewed it as a stand alone piece. This scale of MPs has ended. MP-04Sleep is the only version that interests me here.

I buy the Takara versions so I wait for a MP-11 version of Skywarp and Thundercracker (Takara) that must come one day. Therefore I would avoid the MP-03 versions.

So with the above being said, out of your list i would grab an Acidstorm while they can be found in sales occasionally and keep putting down money on preorders as they are now most often the cheapest way to buy offical MPs.

I assumed you had MP-10. I would buy one if a -$250 price is found.
Maybe try MP-10B to get a feel of the new Optimus. He can be bought for ~$130 minus shipping still and he is pretty cool