If you're planning on using your PC for gaming, what resolution are you running at?
As for component recommendations, switch out the ugly-ass LED case (with two 80mm cooling fans and nothing else... oh my) with a Cooler Master Centurion 5, the mobo for a nicer one from Gigabyte, the X4 620 for an X3 435 (seriously - despite being cheaper, the 435 kicks the 620's butt in most cases, including gaming), and you're good to go. Normally I'd suggest a nicer PSU too, but you seem to be on a tight budget and an Antec PSU won't kill you.
"'Casual games' are something the 'Game Industry' invented to explain away the Wii success instead of actually listening or looking at what Nintendo did. There is no 'casual strategy' from Nintendo. 'Accessible strategy', yes, but ‘casual gamers’ is just the 'Game Industry''s polite way of saying what they feel: 'retarded gamers'."
-Sean Malstrom
