When I was new (read: just get my Streamyx), I did use original client. Then I switch to BitComet and use that for quite some time. Then I have to find another client that allows remote administration, and find Azureus, which I tried to avoid for some time because of bloat, and stays with it since then.

BitComet is, in my opinion, the fastest client around. µtorrent would do well but it was too passive when connecting to peers.

Do you use dialer or a router?

For best results and less hassle, use the WinXP dialer or RASPPPOE.

If you use dialer, the settings are:-

Enable DHT Network: yes
Untick the other 3.
Maximum connection per task: 100
Connection to keep per task: 100
Global Maxmium/Minimum Upload Slots: Auto
Socket Send Buffer Size: Auto.
Socket Start Interval: 100ms
Max half-open TCP Connection: 100. (patch your tcpip.sys file to 200)
Use NAT Traversal via UDP: Auto Detect.

Do port-forwarding first, read the modem manual on how to do it.

Then just apply the above settings.

That torrent have seeds?