Well everyone has their own opinions, there is no "best" parking service, you'll probably get 10 different answers here. Namedrive is ok IMO, I use them almost exclusively for non-english speaking traffic because they have good support for that. I really like Trafficz even though most hate them. I really hate Sedo even though most people love them. Fabulous is good but the reporting interface is annoying, and they're pretty strict about domain quality.
You really have to try a few on and see how they work. There's nothing wrong with having many parking accounts and testing them all to find what works best for you. Also some names just do better at certain parking companies, so move them around once a month until you find the best home for each domain.