Its really easy to throw silly money at amiga's these days, but if you really want to throw money at it, yeah get the graphics card, but then you'll want a fast cpu, more RAM etc. ( Or just boot up WinUAE and pocket the money: RTG on WinUAE generally works very very well )
IMO just add some ram (but I've found as low as 4 MB gets a lot done on an amiga), a bigger hard drive is nice, and just enjoy the ECS chipset. Having a VGA output is nice too
