First time build questions

I am planning to build my first ever desktop computer and I have questions about the components I am going to use. The only thing I am worried about is if I am over powering this build more then I need. What I mean is well... I'm not going to get an intel i7 processor when all I am going to use this computer is for multitasking and very very little gaming. Maybe only Civilization V. That parts That I got were as follow:

APEVIA X-TELSTAR-BK Black Aluminum ATX Full Tower Computer Case

ASUS P8B75-V LGA 1155 Intel B75 SATA 6Gb/s USB 3.0 ATX Intel Motherboard

Intel Core i5-3470 Ivy Bridge 3.2GHz (3.6GHz Turbo Boost) LGA 1155 77W Quad-Core Desktop Processor Intel HD Graphics 2500 BX80637i53470

ENERMAX NAXN 82+ ENP650AWT B 650W ATX12V 80 PLUS BRONZE Certified Active PFC Power Supply

SAPPHIRE Radeon HD 7750

and well the other components aren't really important. But I am really just worried if I really even need this Video card, Does any body think its too much for what I need? I would get a cheaper one but I don't really want to lose performance. Like I said this computer will be used for multitasking like E-mails, youtube, microsoft word, and probably a few open web pages, and video chatting, For college work, You know? I really want to keep my budget under $600. I am willing to go alittle higher for taxes and stuff but no more that $700. I know most of you will say IF I'm am only multitasking I don't need a i5 processor and to just go with the i3, but I want a computer that be able to multitask with NO PROBLEM. I don't want to get componets that will just barly be "good enough". I am open to see what mobo, CPU combos I should use. Is a 650w power supply an overkill? Should I just get a 500w one? How many watts does this video card use? I just don't want a PSU to be working a 100 all the time. And should I buy 3rd party cooling fans or will the case fan suffice? I am not going to overclock because frankly, I don't know how. Haha.
What does everyone think about this build???