It depends on what you are going to use the computer for.
If you are a gamer and you can wait and save a bit, the i3-2100 and the 6870 would last you a good while. The integrated graphics in the 2500k are not going to help in gaming.
If it is just a general computing type machine, the G620 would be enough alone.
I am a gamer but mostly play on consoles, but thats mostly due to this ancient computer I am currently using. That said, I would like to be able to play some games, namely Batman Arkham city which came free with my Samsung SSD. Would like to be able to play at 1920x1080 with good settings and frame rate.