Is the 1gig gts 450 graphics card good for gaming

Depends.
the long answer:
what kind of budget constraints are you in? The gts 450 is a lot of bang for the buck, but so are other, slightly more expansive graphics cards. If you REALLY need to stay below 150 bucks, you can't do much better, but for only 30 dollars or so more, you can get a gtx 460 768mb version which is a much better card.

what resolution are you playing at and what games are you planning on playing? if it is anything around 1080p and you are planning on wanting to play games like metro 2033 with DX11 on anything above low, then you'd need a stronger card.

the short answer:
Yes, but definitely not the best.