If you don't know which one you need, x86.
It's also very difficult to recommend as we don't know your system specs, how/if you'd benefit from x64 architecture, if you can even run it...etc.
See #9 here.
My Computer
At a glance
Windows 7 Ultimate x64AMD Turion(tm) 64 X2 Mobile Technology TL-563GB Nanya PC2-6400 DDR2-SDRAM SO-DIM (400MHz)NVIDIA GeForce Go 7600 256MB GDDR3 SDRAM
Logitech Z2300 Speakers/ Bose Noise Cancelling Headphones/Avermedia PCI-e Hybrid TV Bravo/Epson NX415 all in one/ 4 Port Powered USB Hub/ LG 10x Bluray Burner /TSST Corp DVDRW External
Macbook with 2.1 GHz Intel Core 2 Duo
4GB RAM
120GB had drive
Intel GMA X3100 graphics processor with 144MB of shared DDR2 SDRAM
Built-in iSight camera
Built-in AirPort Extreme Wi-Fi
Built-in Bluetooth 2.0
One FireWire 400 port
Two USB 2.0 ports
Built-in Gigabit Ethernet
I don't know whether the advisor will run unless I install some version of Windows first.
It's important that I know ahead of time whether to get 32bit or 64bit.
Thanks for your help.
My Computer
At a glance
Windows 7 ProfessionalIntel Q9400 @ 2.66GHz8.00 GB