Genesis

Blades Of Vengeance - http://accumulator.webz.cz/download.htm
Some ROM Images.

Consoles - Megadrive - http://www.emulatronia.com/consolas/md.htm
A table of the latest emulators and their ratings.

DCGen - http://sourceforge.net/projects/dcgen/
A Dreamcast port of Generator.

DGen - http://www.bannister.org/software/dgen.htm
Open source emulator port for MacOS.

DGen/SDL - http://www.pknet.com/~joe/dgen-sdl.html
Open source emulator port to Unix/SDL.

FreeRoms: Genesis - http://www.freeroms.com/genesis.htm
Alphabetic sorted ROM list with rating system. (607+ ROMs)

Gametown - http://www.familydomain.com/gametown/sega.html
Offers a few ROMs.

Genecyst - http://bloodlust.zophar.net/gen/genecyst.html
Freeware emulator for DOS.

Generator - http://www.squish.net/generator/
Open source emulator for AmigaOS, DOS, Linux, MacOS and Win32.

Genesis Plus - http://cgfm2.emuviews.com/genplus.php
An open source emulator for DOS, MacOS, and Windows by Charles MacDonald and Richard Bannister.

Genital - http://www.trzy.org/
A freeware emulator for DOS.

Gens - http://gens.consolemul.com/
An open source emulator for BeOS, Linux, and Windows. Multilanguage and Sega CD support.

Megasis - http://www.geocities.co.jp/Playtown-Spade/3163/
Freeware emulator for Windows.

PGEN - http://pgen.gamebase.ca/
An open source emulator for PlayStation2 based on Generator.

PicoDrive - http://picodrive.acornarcade.com/
Open source emulator for RISC OS. Originally developed for mobile devices such as PDAs and mobile phones.

retroDrive - http://www.tmeekins.com/retrodrive.htm
Freeware emulator for Windows. Supports 32X. Previously known as Gensx and Vegas.

Virtual Genesis - http://ourworld.compuserve.com/homepages/JASONMEEHAN/VGEN.HTM
Freeware emulator for DOS.

Xega - http://www.eidolons-inn.net/tiki-index.php?page=Triton
Freeware emulator for Windows. Supports 32X and Sega CD.