How much are my desktop and laptop worth?

[vaio-fx]

I would like to sell both my desktop and laptop on ebay as they are both becomming quite outdated with the intention of replacing them with a new high end laptop. How much should I accept for them (£s)? Would I be better off selling the desktop complete or as parts?

Desktop:
Windows 7 Home Premium 64-Bit
Intel Core 2 Quad Q9400 2.66GHz
4GB DDR2 800MHz RAM
XFX GTX 260 XXX Edition 896MB (pretty sure its NOT the Core 216 version)
500GB 7200RPM Sata HDD
320GB 7200RPM IDE HDD
Sony DVDRW DL Lightscribe burner
Sound Blaster Fatal1ty
Jeantech Storm 700W PSU
ASUS P5Q SE Plus P45 Motherboard
Zalman CPU Cooler
Coolermaster HAF 932 Case
Wifi PCI Card

Laptop:
Dell XPS M1710
Windows 7 Home Premium 64-Bit
Intel Core 2 Duo T7200 2.0GHz
NVIDIA GeForce Go 7900GS 512MB Dedicated
4GB DDR2 667MHz RAM (3.25 addressable, chipset limitation)
500GB 5200RPM Sata HDD
DVDRW
1920x1200 glossy display

Thanks for any replies