Dell 580 help pls

We are moderate gamers---Age of Empires, Farm Frenzy, Zoo Tycoon, Sim City, those type of games

I also do QuickBooks, Quicken, Works, photo scape, tons of genealogy, web surfing, email, facebook games, etc

I am wondering about

#1
Inspiron 580 w/ Core i5-750 2.66GHz, 4GB, 1TB, DVD+-RW, ATI Radeon HD 5450 1GB DDR3, Dell 19 in 1 Media Card Reader, Windows 7 Home Premium 64bit

#2
Inspiron 580 w/ Intel Core i3-540 3.06GHz, 4GB DDR3, 500GB HDD, DVD+-RW, 512MB NVIDIA GeForce G310, Dell 19 in 1 Media Card Reader, Windows 7 Home Premium 64 bit


I know I want 3-4GB Ram, I don't need a huge hard drive. I had a Inspiron 530 for 4 years until the other day when it just quit working.......grrrrrrrrrrrr and before that a Dimension E510 which is still running, just very slowwwwwwww

I have an HP2009m monitor that I bought about 8 months ago.

I do not know which is the better graphics card, that will last, play the games not freeze up the system nor get to hot....