Additional Comments: I NEVER want to experience FPS lag. I don't mind if I have to play a game on mid settings. This is my biggest concern when it comes to buying a graphics card/processor; I don't mind having a less powerful card as long as I can play the games below without a problem:
I have a DVD writer from my old 2005 HP desktop... it should be compatible with any build, right?
The 550 ti is somewhat overpriced for its performance. If you can shell out a bit more cash than the radeon hd 6850, 6870, or gtx 560 will give you more bang for your buck. If you want to stay in that price range than the radeon hd 7770 will be your best bet as nvidia has not yet released low range 600 series cards. Note that you can get away with only a 300w psu if you use an hd 7750.
You don't need an h77 mobo. Save yourself some cash and get a cheap asrock h61 mobo, but note that h61 can only utilize ram up to 1066/1333 depending on the model and if you want to utilize the 1600 speed then you will need a b75 mobo which is still cheaper than the h77. You honestly won't notice the difference in ram speed if you arent overclocking your cpu (which you can't).
The old dvd drive will work if its sata but chances are its ata.