You havn't said which Mac you have, i hav an iMac LCD G4 computer... and have recently done this: following my DVD drive going belly up....
Having "upgraded" to OSX 10.4 the computer had slowed down quite significantly obviously a bit bloatier than previous versions!
Browsing the internet was starting to get annoying, downloading pages had slowed right down. Loading programs had become a bit of a lottery...
The 2GB has definately replaced the speed and improved the performance past my PC again (it had started to lag behind), well worth doing.
The upgrade in total cost me £350 ish: (including a new printer and a memeory stick!) All from Ebuyer:
Item: Seagate ST3300831A Barracuda 300GB 7200RPM ATA/100 8MB Cache - OEM
Qty: 1
Cost: £58.50
Item: Pioneer DVR-111DBK 16x DVD±RW Dual Layer Internal IDE (Black) - OEM
Qty: 1
Cost: £24.94
Item: CRUCIAL 1GB DDR PC2700 333MHz 184-PIN UNBUFF Memory Module 128MX64
Qty: 1
Cost: £53.54
Item: Crucial 1GB DDR PC2700 333MHz 200pin SODIMM 128mx64 for notebooks
Qty: 1
Cost: £79.77
Item: Ebuyer Extra Value Pst700-it1 Thermal Compound Silver Grease Injection Tube
Qty: 3
Cost: £0.38
Item: Ebuyer Value 1GB Aluminium Alloy Slim Sized USB2.0 Flash Drive Retail Boxed
Qty: 1
Cost: £16.39
Item: Canon PIXMA iP4200 Photo 29/19ppm 9600x2400dpi USB
Qty: 1
Cost: £50.20
