With 4 disks should I go for RAID 5 or RAID 10

Hi list,

I am building kind of a poor man's database server:

Pentium D 945 (2 x 3 Ghz cores)
4 GB RAM
4 x 160 GB SATA II 7200 rpm (Intel server motherboard has only 4 SATA ports)

Database will be about 30 GB in size initially and growing 10 GB per year.
Data is inserted overnight in two big tables and during the day mostly
read-only queries are run. Parallelism is rare.

I have read about different raid levels with Postgres but the advice found
seems to apply on 8+ disks systems. With only four disks and performance in
mind should I build a RAID 10 or RAID 5 array? Raid 0 is overruled since
redundancy is needed.
I am going to use software Raid with Linux (Ubuntu Server 6.06).

Thanks for any hindsight.
Regards,
Fernando.