Hotel in Frankfurt

Not inexpensive; but very convenient; is the Sheraton at the airport. There is a walkway from the hotel into the airport terminal. You will be able to take a train into the old Town area and walk around when you arrive, and then back to the hotel that night. (stayed there a while ago)

I (single woman) have stayed at the Ibis Centrum in Frankfurt. It's a 10 minute walk from the train station, less to the tram stop that takes you to Old Town (which is about a 1/2 hour walk). If you book, nonrefundable, 3 weeks in advance through the hotel website (or Accor Hotels website) you usually get a €10 discount. Clean, comfortable, windows open, self-controlled A/C unit. They have a computer and free wifi in the lobby, too. Trains to/from the airport run frequently and take about 20 minutes. If your luggage isn't checked through, best to leave it in storage at the airport. If you stay in the city, you can enjoy Frankfurt till the very late hours - there is quite a bit to see, even after all the shops and sights have closed. The only caveat - the Ibis has the all-in-one soap, so you might want to bring your own.

Trip from Frankfurt to airport takes 11 min. with a train every 15 min. Suggest Hotel Monopol or Excelsior Hotel, which are by the South exit of the Hauptbahnhof. The Ibis is nice though too, with its' location on the Main river.

I stayed at the Ibis in Frankfurt and it was fine... nothing exotic, but convenient to city as well as the airport.

Thank you all for your suggestions! I appreciate it.

...and there is now a new Park Inn right at the airport... and a Hilton Garden Court... and a Hilton... my favorite is the Steigenberger.

Stayed at the Ibis Frankfurt. Modern decor, free shuttle to and from the airport, around $110US when we were there. Breakfast not included but you can pick something up at the airport.

The Meininger is just fine. It's fairly new, and a lot of airline personnel stay there.