I can't seem to find any threads about this subject. Does anyone have a recommendation as to where to watch a good bullfight? I know where the venues are - I am just wondering about whether they are different from each other and which are the favorites.

It depends on when you happen to be where. The bullfight season probably begins around mid-March with the San Jose festivals in the Valencia area; next is Sevilla's Feria de abril (12-18 Apr). The 'big name' Toreros will usually return to Spain (from S. America) for those events. From around Madrid's San Isidro (15 May) festival (which now runs the whole month of May) you can usually find good Corridas or Novilladas any Sunday in any city of any size.

I have seen so many bad bullfights at las Ventas that I really prefer to go to Vista Alegre and take my chances of seeing a good Novillada there. Not to mention that it's quite a bit less expensive if you go to Vista Alegre or Leganes to see a bullfight.

BTW
A Novillero has not yet been confirmed as a full-fledged bullfighter (Torero). He needs a Torero to be his Padrino as he completes a ritual de tomar la Alternativa. Prior to that, he is limited to fighting 2-year-old bulls.

If you are in Spain in the Summer, try to see a "corrida" at the bullring in Puerto de Santa Maria, considered one of Spain's finest.

Some people that follow the bulls look for bullfighters such as El Cordobes, Jesulin de Ubrique or Francisco Rivera Ordonez, whose careers as "toreros" really seem to be a sideline to their careers as figures in the Spanish "rose" press. Serious bullfighters to look for are El Juli, El Fandi, Juan Padilla, Enrique Ponce, and I'm sure others who are aficionados will have names to add to that list.
The traditional first bullfight of the season is Easter Sunday in Seville.
If you are in the South in September, there is an interesting "Corrida Goyesca" in the Plaza de Toros of the pretty town of Ronda. Its bullring is one of the oldest and most beautiful and the bull fighters wear the costumes of the 19th century...

When you get to Spain, go to a newsstand and buy a magazine (revista) called el Ruedo. It will provide you much information about this year's schedules along with feature articles about Toreros.

I tried to find a website but no luck.

No matter where you finally decide to watch a bullfight, I must forewarn you that the last thing you'd want to do is to attend a bullfight without any preparation and totally "naked" for lack of a better term. I can't even begin to count the number of tourists I've talked to who have attended bullfights for the first time, totally unprepared, and were completely turned off by it and ended up never attending another one. All they saw was a bloody spectacle and didn't even realize what they were missing and what a wonderful sport it really is.

Here are 2 suggestions. First, you should try to attend the bullfight with a guide, an afficionado, if you will, who can show you the different nuances of the sport. The other alternative is to do some reading about the sport beforehand and there are numerous books on the subject. The one that I would recommend, believe it or not, is a book by Hemingway entitled "Death in the Afternoon". This is something you can read on the plane and Hemingway's style is so casual and easy to read and he is such a good storyteller that you won't have any problems finishing the book. Granted, this book is a novel, but it contains so many factual information about bullfighting and is a good introduction to the sport. This book may be a bit dated, in terms of the people he refers to, but a lot of information is still valid today.