uTorrent, the BitTorrent client that is:

Micro-Sized Yet Feature Filled
* Most of the features present in other BitTorrent clients are present in uTorrent, including bandwidth prioritization, scheduling, RSS auto-downloading and Mainline DHT (compatible with BitComet). Additionally, uTorrent supports the Protocol Encryption joint specification (compatible with Azureus 2.4.0.0 and above, BitComet 0.63 and above) and peer exchange.

Resource-Friendly
* uTorrent was written with efficiency in mind. Unlike many torrent clients, it does not hog valuable system resources - typically using less than 6MB of memory, allowing you to use the computer as if it weren’t there at all. Additionally, the program itself is contained within a single executable less than 220 KB in size.

Skinnable and Localized
* Various icon, toolbar graphic and status icon replacements are available, and creating your own is very simple. uTorrent also has support for localization, and with a language file present, will automatically switch to your system language. If your language isn’t available, you can easily add your own, or edit other existing translations to improve them!

Actively Developed and Improved
* The developer puts in a lot of time working on features and making things more user-friendly. Releases only come out when they’re ready, with no schedule pressures, so the few bugs that appear are quickly addressed and fixed.

Developer: Ludvig Strigeus
License: Freeware
OS: Windows All
Size: 0.26 MB
Download uTorrent 1.8 build 11200 RC1 link

BitComet is a BitTorrent/HTTP/FTP download management software, which is powerful, fast, very easy-to-use, and completely FREE. It contains many advanced features for BitTorrent download and extends its leading BitTorrent technology to HTTP/FTP to accelerate downloading up to 5 - 10 times faster, or more.

BitComet features:
* Video Download - any video from any site!
o Now able to download any video/mp3/flash files from ANY website

* BitTorrent Download - fast and powerful
o Torrent Share: Exchange torrent while downloading
o Preview while Downloading: Preview of MP3, rmvb, wmv, and qt is available during downloading process.
o Align File to Piece Boundary: Better for making torrent, fully compatible with old versions.
o Intelligent Connection Optimization: Configuration is automatically set to match your connection type.
o Intelligent Disk Cache: Memory cache is used to reduce the read/write frequency of your hard drive, therefore increasing service life.
o Quick Resume: The torrents can be seeded or resumed immediately without time consuming scans.
o Auto Config ICF (Internet Connection Firewall) and ICS (Internet Connection Sharing) in Windows XP
o Auto Config UPNP port mapping in router (UPnP support is required in router, Windows XP is required).
o Option of Disabling and Setting Priority of Files in any torrent: Files can be disabled, so they are not downloaded, or set to higher or lower priority, allowing you to select which files finish first.
o Also support Multi-tracker, DHT, utf-8 extension, and UDP tracker Protocol v2.

* HTTP/FTP Download - Innovative P2P Technology
o P2P downloading: BitTorrent technology is integrated into HTTP/FTP download, with which BitComet automatically finds other clients and gets data from them to increase your download speed，without additional bandwidth usage of the HTTP server.
o Intelligent File Rename: Automatic choose the best name for your download file.
o Preview while Downloading: Preview of mp3, rmvb, wmv, and qt is available during downloading process.
o Multi-Mirror download: Mirror servers are automatically found for the file being downloaded. Data from these servers are downloaded at the same time to increase download speed 300% or more.
o Multi-Section download: Files are split into several sections which are downloaded at the same time to increase the download speed up to 500% or more.
o Multi-Language Support: Multi-language web pages and encoded URLs can be correctly handled.
o Quick Resume: Stopped download tasks can be resumed from where they left off from both HTTP and FTP servers.

* Download Management - Customization Available
o Global and Per-Task Speed Limit, for Both Upload and Download.
o Bandwidth Scheduler
o Custom-built Categories Management.

* Easy to Use and Free!
o User-friendly and very easy-to-use, we try to hide every complicated terms behind the interface
o BitComet does not contain any adware or spyware.

Developer: BitComet
License: Freeware
OS: Windows All
Size: 6.1 MB
Download BitComet Build 20080530 Beta link

FrostWire is a program like very popular LimeWire PRO Gnutella/Bittorrent client.

FrostWire features:
* Completely Free & Open Source
* Firewall-to-firewall transfers
* Turbo-Charged Download Speeds
* Absolutely NO Spyware or Adware
* Connects to more sources
* Creative Commons license support
* Max. speed network connections
* Junk Result Filters
* Community Chat Rooms
* iTunes Integration
* BitTorrent Support
* Proxy Support

Developer: FrostWire, LLC
License: Freeware
OS: Windows All
Size: 7.3 MB
Download FrostWire 4.13.5 link

Get BitTorrent and harness a community of over 150 million users to deliver files to your PC faster than anything else.

The new BitTorrent for Windows brings together BitTorrent’s proven expertise in networking protocols with µTorrent’s efficient implementation and compelling UI to create a better BitTorrent client.

BitTorrent features:
* Lightweight client
* Local peer discovery
* Configurable bandwidth scheduler
* Global and per-torrent speed limiting
* RSS Downloader
* Always Spyware-Free

Developer: Bram Cohen
License: Freeware
OS: Windows All
Size: 0.8 MB
Download BitTorrent 6.0.3 link

Torrent Searcher is a easy to use multiple network filesharing program. A multiple filesharing program means that it can connect to different filesharing networks like Fasttrack, Gnutella, OpenFT and Ares.

Changes from 8.0 to 9.0:
* Updated Gnutella plugin to version 0.0.11 without time bomb
* Added Turkish translation
* Added ‘Find File in Library’ to search result menu
* Added manual update check to help menu
* Added ‘Hide Files with only one Source’ to search result menu
* Added ‘Time Found’ column to search results
* Added ‘Find Video on YouTube’ to library
* Added IP of remote giFT to status bar when remotely connected
* Added Bitzi lookup to search results and library
* Update Italian translation

Torrent Searcher Screenshot

Developer: Robert Keus
License: Freeware
OS: Windows All
Size: 4.5 MB
Download Torrent Searcher 9.0 RC1 link