i read somewhere that FFXIV will have full DX11 support, so for full gfx you'll need a DX11 card
Taken from the Tanaka & Komoto Interview:
In regards to the PC version, the game will utilize the most current version of Direct X that is out when beta testing begins. This goes for Operating System as well. Similarly, they do not specify Vista or Windows 7 as an operating system, saying again that it will depend on what is out at the time. For those of you looking to prep a new PC, Tanaka claims they are really looking to get on the cutting edge of technology with this installment. Like Final Fantasy XI, the game specs will be extremely high for the time, but in about 5 years, an average machine can run it on max settings with little to no issues. Tanaka also expressed interest in making a benchmark program available.
I doubt any laptop will be able to run it as good (if at all) as a normal desktop machine if that statement is true.
If you ask me I guess the mimimum requirements will be something like:
Operating system: Windows XP/Vista/7
CPU: Dual Core with 2,2GHz
Memory: 2GB DDR2 RAM
Graphics: DirectX10 (or if avaliable DirectX11) compatible card with a minimum of 512MB RAM
Harddisk space: ~20GB