one last thing I want to say here if you are buying E2180:
E2180 is much more costlier than E2160, while offering only a 200MHz increase in clock speed.
E2140 - 1.6GHz - Rs. 2500
E2160 - 1.8GHz - Rs. 2700
E2180 - 2.0GHz - Rs. 3300
as you can see, the first two are much more VFM compared to the third. As usual, intel is phasing out the first to and introducing the third only to extract more money from us.
Its a fact that E2160 can effortlessly go beyond E2180's clock speed, and can safely reach 2.4GHz and can go upto 3.4GHz safely with stock cooling.
The same goes for E2140.
So I recomend that you buy one of the first two instead of the second.
And about the importance of L2 cache, the 1mb extra l2 isn't worth the 2500 extra you spend on E4500. It hardly influences the performance in games, especially so when compared to the increase offered by spending that extra cash on getting a better GPU.
But the same case is not valid for the quad core, where 3k more is to be paid for getting 6mb more l2 cache for a quad core cpu. Those are performance CPUs, and with 4 cores, every mb of l2 cache matters, and hence 3k for 6mb l2 extra is worth every bit of the money you pay.
My current advice to you: buy the E2160 or E2140 first, get a cheap and good quality OverClocker approved motherboard, and use the money you save from buying E2160 on either getting a better board(recomended if no GPU) or a better GPU, if you are buying it, or just save it for the future.
Later, you can buy the Q3450.
Here is a thread by a user called aXXo, who set up one of the most perfect budget OverClocked systems ever, and enjoys a great performance from his CPU.
*www.thinkdigit.com/forum/showthread.php?t=79863
take a look there and see if you are upto it, because if so, just follow his steps(as he was successful) and you may have an uber rig.