In any Vampire Counts force, Vampires will be the black and bitter heart of your army. The most important characters you have are Vampires, and Vampire units (Blood Knights, Varghulf, and Black Coach) make up some of the strongest and toughest in the army. No matter what kind of playing style or theme you have chosen for your force, Vampires will play a significant part in all of your battles.

There is no reason not to have them, since there are only benefits to being a Vampire! The biggest advantage is that units within 6" of a Vampire can march, just as if they were within 12" of the general. This means that you can spread out your army and still keep up a decent speed of advance, so long as you have a couple of Vampires spread out with them. Another natural bonus is that Vampires don't have to check for "crumbling" if the general dies -- quite handy since your other units have a relatively low Leadership. By including a Vampire unit or two, there's no reason to give up hope if you do somehow lose your precious general.

Vampiric characters are probably the most versatile characters in Warhammer and can be tailored for a number of different tasks to suit your playing style or strategy. The Vampire and Vampire Lord are both wizards as well as good fighters as standard, so their abilities can be boosted in either direction, or kept as a balanced mix. Vampires have access to a large number of Vampiric Powers, along with magic items, and it is from combining the two in different ways that a Vampire's personality and battlefield capabilities are derived. Vampiric Powers can be mixed freely and more than one Vampire can take any given power. They do not count towards your magic item allowance either, so you can really go to town when creating your characters.

A word of warning though: do not overspend on your Vampire characters. With so many options and the potential to spend highly on characters, it is very easy to give them too much and make them too expensive. Spending 900+ points on characters is quite easy in a Vampire Counts army, but if you play a 2,000-point battle this can leave you perilously low on units. Your Vampires are really dangerous, but they need units to support them to be successful. It is better to sit down and figure out exactly what you want your Vampires to do, give them the equipment to do that but nothing more, and then use the spare points to get more units. Your Vampires will be slightly less nasty overall, but it will give you greater tactical flexibility across your army, which will often win you the battle in the end.