I'm going to be getting some fat money on January 1 - payroll has been shafting me.  I was thinking about getting a new Mac.  My 900 MHz G3 iBook (640MB RAM) has been good to me, but I feel like I need a G4.  And Tiger.  Apple sells refurbished G4 iBooks with 512 RAM, 1.42 GHz processor, and 60GB HD.  Preloaded with Tiger and Airport Extreme for $1099.  That's what I am thinking about getting.  Add an external Firewire drive (LaCie, $200) and another 512 RAM, and you've got a machine that sounds kickass.
I'm pretty set on the portables - I love carrying my computer to the bar and surfing while drinking, and other portable benefits.  Is this a good deal?  Is the G4 going to be geometrically better than the G3?  Is this even a decent computer?  My G3 was $999 stock, and I think I can get a couple hundred for it my local Apple Store.  I feel like this would be a worthwhile upgrade.
Any thoughts?