Most people (including me) will recommend a "normal" focal length for your first lens. A "normal" focal length for 4x5 is considered 135mm to 180mm. A 210mm is considered a long "normal". The 210 is probably your most versatile lens for 4x5. It's a great focal length and most 210's have lots of coverage. They are also dirt cheap right now.
A lot depends on what/where you're shooting, here in the UK I find I tend to need a wider lens, I'd be hard pushed to use a 210mm lens as my sole lens, it's like using a 75mm on a 35mm camera.