liquid_zombie - i never heard of a 7300GT with DDR3 ram, its only specific to that brand so i assumed it was a missprint.
due to that fact... That specific 7300GT is not bad. (Remember Only that 7300GT) any other 7300GT will perform similar or worse then a stock 6600.
Remember, the benchmarks you linked to are comparing the:
6600GT = 500/1000
7300GT = 500/1400 (Inno3D)
7300GT = 640/1600 (Inno3D) (Custom Overclocked)
(Just a Reminder a Stock 7300GT = 350/666, Will not play anything modern without lagg).
Also Remember: a 7600GS is still better then a 7300GT with High Clocks.( a stock 76GS 400/800 12pipeline card will perform similar to the OVERCLOCKED Inno3D 7300GT(640/1600) (Except the 7600GS wont need Overclocking).
So remember if the 7600GS is near the same price, go for that instead.
...and also dont foget, just cause the Reviewer could overclock there gernerouse Sample card of the Inno3D to 640/1600.... Does not mean you will have similar resaults. each card has its own limits... and 500/1400 -> 640/1600, looks like the limit.. witch would be lucky to reach and would shorten the life time of the card if remained at such high clocks.