I need a graphics card that can support, at the same, time 3 displays of 22"-24" and one connection (preferably HDMI) towards the TV set for movie watching. Any suggestions whether I should go for few SLI/CrossFire cards or workstation card? And what cards would you recommend?
Those 3 displays would be used for 2D (mostly coding and development), ie nothing 3D intensive - not even games.
Any of the AMD 7 Series can handle this. If you want to game at all go with something like a 7950. If not gaming you can go with one of the lower cards. I run my 7950 with 3x 24 inch screens, and a 39 inch TV. Keep in mind, at least 2 of the monitors will have to be displayport or you will need a displayport to DVI adapter (about $22).
The AMD 7 Series can theoretically handle up to six displays, but only a few cards do have the ports to connect more then three displays without crap, like splitting the DVI channels. The PowerColor AX7770 1GBD5-2DH was the cheapest i could find and that's a PCIE 3.0 card, so compatibility with your mobo needs to be checked.