DELL Internal PCI 802.11b/g Wireless Network Card

[Sedated]

I was about to place a order with Dell earlier for a new Desktop PC and wanted it wireless so I went with this spec

PROCESSOR Intel® Viiv™ technology - Intel® Core™ 2 Duo E6550 processor (2.33GHz) edit
OPERATING SYSTEM Genuine Windows Vista® Home Premium - English edit
HARDWARE SUPPORT 1 Year Base Warranty - Collect & Return edit
MONITOR No 20" Wide Monitor edit
MEMORY 4096MB 667MHz Dual Channel DDR2 SDRAM [4x1024] edit
HARD DRIVE 500GB Dual Hard Drive Non RAID (2x250GB - 7200rpm) edit
GRAPHICS CARD 256MB nVidia™ GeForce 8600GT graphics card edit
OPTICAL DRIVE 16x DVD+/-RW & 16x DVD Drives edit
KEYBOARD Dell™ Entry Quietkey USB Keyboard - UK/Irish (QWERTY) edit
MOUSE Dell 2 Button USB Scroll Optical Mouse - Black edit
Accessories
SOUND SOFTWARE Sound Blaster® X-Fi Xtreme Music PCI Soundcard edit
SPEAKERS No Speakers edit
FLOPPY/MEDIA DRIVES 19-in-1 Media Card Reader edit
MODEMS No Modem edit
WIRELESS NETWORKING Internal PCI 802.11b/g Wireless Network Card edit

Now the salesman has tryed to talk me into going with a Berkin f5d7050 wireless USB adapter as he said it would be a better option. I cannot figure out why, is it to do with performance of the PC? not enough space inside, or just a better piece of kit? Please help as its doing my head in.

Also If I had the internal one installed and it wasnt any good couldnt I just disable it? and use one that will probably come with my Router (once I get wireless Broadband package)

To confuse me more I went on Dell live chat (oh what fun that was!) and he recommended the Internal Quote "The Internal PC I wireless network card would be the best option as it comes with a better bandwidth" .

I desperatly need a new PC TODAY!!
Help!!!

The salesman also said If I had the internal card and it wasnt very good, If i then also put a dongle in the USB port instead I would get conflicts? This cant be right can it surely i could just disable the Internal card?

[Uridium]

Just go with the internal one, no point in wqasting a USB port you don't have to.

and yes you can always disable or just remove the PCI one whenever you want

[beerhunter]

The salesman was talking rubbish. For technical, reasons a mini-PCI internal adapter will always be better than a USB one.

Mini-PCI is also more practical.