Laptop Hard Disk Upgrade?

[The_Burg]

Currently have Compaq Presario V5245eu, standard drive is 4200 spin, how much difference would a 54000 or 7200 drive make?
Size not particularly important only needs OS and basic apps.
I have a 40gb 5400 external 2.5 drive already which i could fit but is it worth going 7200?
Or would more RAM be better? Standard is 2x 512mb so upgrade would be expensive as 2x 1gb would be required.

[The_Burg]

Max RAM is 2gb, to upgrade would need 2x 1gb modules.
Cost around £140 so not really financially worth it.
Hard disk only needs to be around 40gb so would be quite cheap upgrade.