I think it would be interesting to see what people feel the major decision factors are when choosing a dedicated host. I think a good list could really help alot of people.
Here are some of the factors I am currently looking into, I tried to place them in my own rank order. Try ranking them in priority order based upon your personal experience:
Service - (managed, per incident, what's included in standard package, hourly rates for service)
Amount of RAM
Amount of Disk Space
Type of Ram (PC100 - ECC) - thanks to romero for that tip
Type of Hard Drive (IDE, EIDE, SCSI, 7200 or greater RPM's)
OS (Linux, Windows, etc.)
Service availability - when can you actually speak to a person to have service performed (24/7, work hours - do they charge more after hours? What is the average turnaround time to perform simple services (i.e. reboot, software install, etc.)
Minimum Contracts (do they force multiple month contracts up front or do they go month-by-month)?
Upgrade Policy (can you upgrade during a contract, what does it cost, how long does it take)
Word of Mouth - What current users say about the service
Software Preinstalled - security of software (Linux
Version, PHP, MySQL, SendMail vs. Qmail, Telnet vs. SSH, WuFTP vs ProFTP)
Is remote access standard (ssh or telnet, root access)
Bandwidth or Transfer per month(do they measure using bandwidth or transfer, charges for overuse, upgrade costs.)
Do they measure actual bandwidth or use the 95th Percentile Method?
Ping and Tracert values from sites on their network
Setup Fees (none, high, negotiable)
Additional IP Policy
Control Panel Included (custom, PLESK)
This is all I can think of for now, please feel free to add to this list and give your rankings with your reasons why.