I was asked recently what tools I use on a daily or weekly basis. Here's what I came up with:
mRemoteNG- This is my favorite tool- it combines multiple RDC/VNCmanagement, with Putty, Telnet, and SSH.
Citrix XenCenter- for all your XEN host management needs.
VMware vSphere Client - for all your VMware ESXi management needs.
Putty- SSH and Telnet
TFTPD - TFPT server
Advanced IP Scanner- Network IP scanner
Wireshark - Network Protocol Analyzer
iperf - Network Speed testing
Cisco ASDM- ASA GUI Management Interface
KeePass- Password Management
Filezilla- FTP/SFTP Client
Notepad++- Advanced Text Editor
WinDirStat- Visual File Sizing tool
Supermicro IPMI View- Manage Multiple IP
Clonezilla- System Imaging
7Zip- Archive tool
Crystal Disk Mark- Hard drive performance testing
YUMI- USB Multiboot
Unetbootin- ISO -> USB tool
NiNite- Download multiple tools listed above in a one click installer
I'm sure there's more I am forgetting, but this is my basic "kit". Have a suggestion? Post it in the comments!