Upgrading T400 and upgrading to Windows 7

[Imp]

I just purchased a T400 with the following specs:

Intel Core 2 Duo Processor P8400 (2.26ghz 1066 mhz 3MBL2)
Windows Vista Home Basic
14.1 WXGA TFT w/LED BL
ATI Mobility Radeon 3470 with 256 MB
2GB PC3-8500 DDR3 (1 DIMM)
160GB Hard Disk Drive, 5400RPM
CD-RW/DVD-ROM, Ultrabay Slim
9 Cell Li-Ion Battery
ThinkPad 11b/g III Wi-Fi wireless LAN Mini-PCIe

I was wondering should I upgrade the ram to 3 or 4 GB or/and upgrade the HD to a 7200 RPM or/and upgrade the Wi-Fi Wireless card to Intel 5100 or 5300? Is it worth it to upgrade any of these? I will be using this computer for mainly word processing, surfing the net, watching movies, and playing games such as starcraft 2 and Diablo 3 in the near future (I don't use photoshop much and CAD not at all)

I am also thinking of upgrading to windows 7 RC...what would I have to do?

Thanks in advance for any response.

[Performa636CD]

I just purchased a T400 with the following specs:

Intel Core 2 Duo Processor P8400 (2.26ghz 1066 mhz 3MBL2)
Windows Vista Home Basic
14.1 WXGA TFT w/LED BL
ATI Mobility Radeon 3470 with 256 MB
2GB PC3-8500 DDR3 (1 DIMM)
160GB Hard Disk Drive, 5400RPM
CD-RW/DVD-ROM, Ultrabay Slim
9 Cell Li-Ion Battery
ThinkPad 11b/g III Wi-Fi wireless LAN Mini-PCIe

I was wondering should I upgrade the ram to 3 or 4 GB or/and upgrade the HD to a 7200 RPM or/and upgrade the Wi-Fi Wireless card to Intel 5100 or 5300? Is it worth it to upgrade any of these? I will be using this computer for mainly word processing, surfing the net, watching movies, and playing games such as starcraft 2 and Diablo 3 in the near future (I don't use photoshop much and CAD not at all)

I am also thinking of upgrading to windows 7 RC...what would I have to do?

Thanks in advance for any response.

I was told upgrading to that WiFi technology just increased your wireless Internet range. Whether you need that or not is up to you.

[ZaZ]

For general usage, a faster hard drive is usually a better upgrade. If you're using a 32 OS, be it XP, Vista or 7, you can't use more than 3GB of memory.