Hotel near Berlin Central Train station

It's about a 20 minute walk through the park (or I THINK you can take the tram) but the Grand Hyatt Berlin is wonderful. The top floor hot tub should not be missed :)

Hotel Motel One Berlin Hauptbahnhof location is one block from the station out the Europlatz door. It’s a clean, efficient modern business hotel. Rooms around a hundred dollars. Great breakfast for about fifteen. Restaurant and bar open late. The only caveat is the rooms are tight on space. I love it for solo trips but a bit claustrophobic with my husband.

There is a very nice Ibis Berlin Hauptbahnhof Hotel out the side door and across the street from the Berlin train station.

We just went to the train station where we caught the city's underground to easily get anywhere in town. And the train from the airport will take you a few feet from your front door.

The tram out front can take you about 1.5 miles and the Berlin Wall Museum is about 100 yards walk around the corner.

That Ibis is decent, clean and relatively inexpensive.

Any recommendations for a reasonably priced hotel within walking
distance of the station?

Since the definition of resonable varies from one person to another, I will agree with both the Motel One and ibis suggestions and add the Steigenberger. I sometimes find a great rate--maybe just 20 Euros more than a Motel One--for a much more luxurious experience.

Like @thenosbigs, I also stayed at the Motel One by the Hauptbahnhof and liked my stay there very much. I did not find it claustrophobic but I was there solo, so that might have made a difference. It was very convenient to the station, though (about a 3 minute walk), quite reasonably priced and also very clean and comfortable. I would definitely stay there again.