Available Direct Connect Clients:

[Deach]

Windows
DC++
oDC
NMDC
JavaDC

Linux
DCGui
LDCC


Feel free to post more and I will add them to this list.

[djnickname]

Maybe people can post which one they prefer and why..

[Profett]

Well, I can already tell JavaDC looks the sexiest. Edit: err wait, maybe that's just *his* theme.
oDC has some extra features which might make it appealing to some, website lists the differences between his and normal.

[MasJ]

Maybe you should categorize them based on OS. Some people want Linux clients.

[Josh]

I have only tried DC++, but from what I have used of it it is really good. It has many features but is strait to the point.

[ccdart]

I'm using DC++, Direct Connect 2 has annoying Sounds, DC++ Kicks.

[Ziegfried]

The JavaDC thing has a Linux port, too. Though it doesn't seem all that great.

[Soeru]

I reccomend DC++, but I've only used this one and the original client. Can't go wrong with a plus version of anything really... *points to Emule plus*

[Cookie Monster]

Some more clients to add to the list:

Linux
DCTC http://ac2i.tzo.com/dctc/
CCCP http://members.chello.se/hampasfirma/cccp/
QuickDC http://quickdc.sourceforge.net/index.php

Mac
NMDC http://www.neo-modus.com/
DCGUI http://dc.ketelhot.de/news.php
DCOSX http://sourceforge.net/projects/dcosx/
Mac DC++ http://sourceforge.net/projects/macdcpp/

There are loads of windows based clients, but I wont be posting em till i know if features as the up/download limiting are allowed.... and of course there are more interesting clients for the Ops