Viewing web movies on a G4, QT, WMP or RealOne?

Hi all,
I've got a cranky old G4 with the following card.

Chipset Model: ATY,Rage128
Type: Display
Bus: AGP
Slot: SLOT-A
VRAM (Total): 16 MB
Vendor: ATI (0x1002)
Device ID: 0x5246
Revision ID: 0x0000
ROM Revision: 113-51809-112
Displays:
Display:
Resolution: 1024 x 768 @ 85 Hz
Depth: 32-bit Color
Core Image: Not Supported
Main Display: Yes
Mirror: Off
Online: Yes
Quartz Extreme: Not Supported


What's the best software to watch Youtube and other videos in, and should I set one movie player as my default?