If you want to be safe on the hardware side, you may want to consider this extremely competitively priced Quad system from
LayeredTech (I have 8 servers there, they have - real - 24/7 support, and the Quad Opteron will be on their Savvis network (former Cable & Wireless, good network)
? 4 x AMD Opteron 842+ w/1MB L2 cache
? 3 x 73GB U320 SCSI Hard Drive (RAID5)
? RAID 1/0/5 or JBOD available depending on OS
? 4GB ECC DDR RAM
? Bandwidth: 10Mb/s Un-Metered (Savvis)
? IP Addresses: 32 (29 usable)
? Private VLAN
? Number Of Servers: 1
? Basic Resource Monitoring
? FreeBSD, Linux, Windows*
? 100% Self Managed and Dedicated
Monthly Fee Options:
? $999.99 (Plus One-time Setup Fee of $179.00)
This system can hold 16 GB with (relatively) cheap 1 GB dimms (and up to 32 GB with 2 GB dimms).
Based on the price for the above system, the same with 16 GB RAM should be around $1,500 / month