Hollandaise is one of the five mother sauces, and a great topping on eggs benedict.  But there are many well known ways to slightly change hollandaise to create a different sauce.

Bavaroise- made with crayfish butter, cream and crayfish meat, common on fish

Bearnaise- Tarragon reduction, fresh tarragon and chevril, common on grilled meat

Choron- Bearnaise with tomato added, commonly served with meat and poultry

Foyot- Bearnaise with Demi-Glace, common on Meats and Offal (oragans)

Maltaise- Hollandaise with blood oranges, (some suggest adding orange zest also) commonly paired with asparagus

Mousseline- Hollandaise with heavy cream, common on fish and asparagus

Paloise- Hollandaise with mint reduction and fresh mint, common on grilled meats

Royal- Equal parts Veloute, hollandaise and whipped heavy cream, common with poached poultry and fish.

Baisc Hollandaise Recipe:

4 egg yolks
12 oz melted butter
2 Tbsp white wine vinigar
lemon juice
salt
peppercorns

1.  Reduce white wine vinigar with cracked peppercorns, by about 3/4 the volume.  Let cool
2.  Add egg yolks to the reduction, and whish over a double broiler.  Remove from heat if mixture is gettign to warm.  When egg yolks triple in volume stop whisking.
3.  Slowly add butter, if hte sauce starts to break add a small aplash of water to it.  If the sauce gets to thick add a splash of lemon juice. 
4.  Finish the sauce to taste with salt, pepper, or cayanne.  Or make another type of sauce form it.

When making Bearnaise, Choron, or Foyot sauce add the tarragon to the vinagar before making the sauce.  Add mint to the vinagar before making Paloise.

Hollandaise sauce is one of the five mother sauces in French cooking along with espagnole (brown sauce- like demi-glace), Veloute (made with white stock), Bechemel (cream sauce), and tomato.

While I was reading the 1998 James Beard Award winning cookbook Cookwise. While reading the section on emulsion sauces I stopped at the hollandaise recipe and reread three times. This recipe was slightly different then the way I was taught to make it. So I decided to look up the recipe for hollandaise sauce in other cookbooks that are highly trusted:
1. Mastering the Art of French Cooking, Julia Childs
2. The Joy of Cooking 75th anniversary, Rombauer
3. Sauces, James Peterson 1991 James Beard Award Cookbook of the Year
4 How to Cook Everything, Mark Bittman, 2009 James Beard Award General Cooking

Each book suggests a different ratio of egg yolks to butter. Sauces and the Joy of Cooking recommend using clarified butter (milk fats removed) and the other books recommend using all of the butter. Julia Childs recommends adding a Tablespoon of cold butter after heating the egg yolks so stop the yolks from continueing to cook. The Joy of Cooking also suggests adding a dash of hot sauce and cookwise says to add cayanne pepper. How to Cook does not recommend adding water to help stabelize the emulsion while whisking.

Whichever recipe you decide to look up and follow will still be delicious, especially if you use the freshest and highest quality ingredients. I'm looking forward to making Eggs Benedict in the morning and using a local hand made butter I found at a Trickle Springs Creamery, Chambersburg. (It looks like Julia Childs recipe has the most butter in her hollandaise recipe, I think I'll follow her recipe this time)