Tools

Web Tools

Microsoft Remote Connectivity Analyzer
Sender ID Framework SPF Record Wizard
IP Address Lookup
File Transfer Time Calculator
Subnet Calculator
Raid Calculator
MX Toolbox - look up mx or any other type of public records
Internet Speedtest - http://testmy.net/, does not require Java
Internet Speedtest - speedtest.net
Internet Speedtest - windstream.net
SSL Cert Tester
Phone Lookup
Netmask Converter
Group Policy Search
Web Page Test - test the performance of a web page
BrowserStack - test websites in any browser
Fax Zero - send free faxes to test your fax machines
whatsmydns.net - check DNS propagation through the world for multiple record types
visualware.com - check internet connection quality to see if SIP will work for you
www.dnsbl.info - check email blacklist status of an IP address
iCalc Bandwidth Calculator

Win Tools

Sysinternals Suite
Royal TS - attitude for your RDP
WinSCP
Wireshark
WinMerge
AD Replication Status Tool

Win Desktop Customizations

Obsidian Cursor Set
f.lux - make your screen darker
Black Carbon Chrome Skin
AutoHotkey - never type the same thing twice
PicPick - all in one desktop tool, screen capture, measure, color picker, etc