A nebula is a cloud of gas and / or dust which is visible in the night sky either as an indistinct bright patch or as a dark silhouette against other luminous matter. Most nebulae within the Milky Way are described as "faint fuzzies" for a good reason, as are most galaxies, so there are very few nebulae in other galaxies which are easily observable with typical amateur equipment - and the Tarantula is the best. It is so intrinsically bright that if it were as close to Earth as the Orion Nebula, it would cast shadows at night!
If you've got access to a
really big telescope, there are some other beauties to be found in the LMC & SMC - e.g. check out "The Odd Couple", which also lies in the LMC:
http://www.eso.org/public/news/eso1335/
(The image in the article was taken with the European VLT, which has an 8.2 metre mirror!)