"Sega" is a manufacturer, not the name of a specific system made by them, though...>_>
Also, that's just a very hodge-podge grouping of systems...Three Ninny homes, Sega something or other, and Sony's handheld...What's with the weird choice? It's like you wanted people to choose SNES by putting it up against systems that mostly don't compete (at least yet as two are current).
The best systems that deserve to be on a "best system" poll that are mysteriously missing are NES, PSX, PS2, GBA, & NDS...and...why not? Let's throw in the Genesis too...