Mmm... there is one problem with Macs, iBooks have 12'' ($999) and 14'' ($1,299) displays, MacPro Book have only 15.4'' display ($1,999). PowerPC G4 has only 17'' display, but it initial price is $2,499.
Alienware: Area-51® m5700 17'' ($1,389), Area-51® m5500 15'' ($949)
Dell: Inspiron E1505 15.4'' ($749), Inspiron E1705 17'' ($999)
Since 1998 I use only 17'' monitors and there is no way I'll go back ot 15''. It's very important for me to have a big sceen size cuz for the next 4 years I'll spend a lot of time working on the laptop and I don't want to seat in front of 15'' monitor, so I prefer PC laptops.
Sites I used:
www.apple.com,
www.alienware.com,
www.dell.com