The best card on the Market atm is the Nvidia geforce 8800GTX 768mb version. The exact best card is more difficult to pinpoint as it will depend on the manufacturer and how new the card is.
The 7500 le nothing compared to it. The 7500 is a HP OEM card that is nothing more than a glorified 7300 card. Its like a budget version of a budget card thats now quite old.