Just about any modern DSLR or even point-and-shoot camera (provided it has manual controls) is sufficient. Don't be afraid to buy last year's model, or even an older used camera. Most cameras made in the past 10 years from the big name makers are perfectly adequate. What's behind the camera is much more important than what's inside it.
Whatever you get, take some time to familiarize yourself with the camera functions and controls. The camera you're most comfortable using will take the best photos. A DSLR will have more convenient controls and may be simpler to adjust, but you can take great pen pictures without interchangeable lenses.
Take a look at
http://www.penturners.org/forum/f24/photography-basics-composition-125808/ and see if you can tell which photos were shot with a $1500 DSLR and which were taken with a $70 point-and-shoot.
Regards,
Eric