Quote: "Geforce GTX 660 ti (vs my current Geforce GT 130M)"
The 660ti is a good card, but maybe you should look into the 760 instead is that is replacing the 660ti and should have the same price
Quote: "Intel i5 3570K (vs my current Intel Core2 Duo P8600)"
Should also work well, you may want to look into a haswell (No idea of the number name) i5 as it is the latest version, I have no idea about the price of them though.
Quote: "Motherboard? [GA-Z77-DS3H]"
No idea, if it fits with the CPU, it should work I believe
Quote: "Memory, is 4 gb still enough these days? [BLE4G3D1608DE1TX0CEU]"
I had to upgrade from 6gb, but I do like having lots of programs running. I would go for 8 gigs as it is fairly cheap anyway
Quote: "SSD [SH103S3/120G] (120gb)"
Personaly I feel that 120 gb is a bit to small, but it depends on how much you want to spend
Quote: "And finally a PSU [CP-9020060-EU] running 45A at +12v"
It should be enough, but im not an expert