The Arcade (cores were cancelled) goes for about $280us and comes with HDMI, a single wireless controller and a 256MB memory unit (not a card per se).
The Pro/Premium runs about $349, comes with a wireless controller, 20GB drive and HDMI port.
The Elite is about $449, comes with a 120GB drive, Wiresless controller, HDMI port AND HDMI cable. Plus the Elites are a cool black color
Any way you go, you can get XboxLive Gold for $50-$60/13months if you buy it all at once. Well worth it. I can't see paying $10/month for each game (like WoW, etc. requires), but 10/month for ALL games is ok with me.
I'll tell you upfront, the lack of a HDD will drive you nuts. The Arcade's 256MB unit is NOT enough space for many games/saves.
Even my son complains about the 20GB drive being too small. Once you get your 360, you'll want to take advantage of xBoxLive and all it's demos, freebies, etc. 20GB isn't enough.
I've had my Elite's 120GB drive down to about 30GB free before cleaning some old demos off.
I say save your money and wait to get an Elite. Then you don't have to worry about anything except another controller for your friend.