Public transportation from Heathrow to DT London.

If it's the Crowne Plaza Hotel in Buckingham Gate the nearest tube station is St James's Park. The best tube route is to take the Piccadilly Line from Heathrow to Hammersmith, and then walk across the platform to change to the District Line in the same Eastbound direction. I don't think it's worth getting a taxi from the station to the hotel unless you can hardly walk and/or have gigantic quantities of luggage (in which case you should probably use a taxi or shuttle all the way). I can't really say how much money to put on the Oyster to start with but probably about fifteen or twenty pounds. The fare from Heathrow will be automatically calculated, but you will each need your own card.

You will probably be better off with a 7 day oyster card for about 27 GBP each (Zone 1 & 2). You can add up the individual trips that you'd take and being "very busy" guarantees you'll hit the daily max. Even when you aren't very busy it doesn't take long to justify the 7 day pass. It's about a 1 1/2 hours to get from Heathrow to London on the tube. A local can probably give a more accurate number. You alternative would be the Heathrow Express (18 GBP) that gets you to Paddington in half an hour or the not quite express (less but I can't remember the cost). I've seen here that you can add money to the travel pass to cover you outside zones 1 -2 (which covers almost all of tourist London) if you want to go to/from Heathrow by tube. Here's the link to Transport for London http://www.tfl.gov.uk/ Look at "Visitor Tickets" in the middle of the page.

Dean, you will both need an Oyster Card. 20 pounds on each seems reasonable. You can always add money. Every time I've taken the Heathrow Express it takes 15 minutes nonstop to Paddington Station The Heathrow Connect is cheaper, but makes a few stops, and takes about 30 minutes. I'm guessing cab fare from Paddington to your hotel will be around 10 pounds. So, Heathrow Express to Paddington and then cab to hotel works out to something less than half what a cab from Heathrow would cost. The Tube is the cheapest. Also the longest, slowest, most crowded, etc. Heathrow-London transport is very much a matter of buying time and convenience.

We paid 10 pounds (including a 1 pound tip) for a taxi from Gloucester Road tube station to Paddington. The taxi drove through Hyde Park to get there. It was on our way home, and we didn't feel like riding the tube to Paddington with all our luggage (which was heavier than when we arrived 10 days earlier). Cabs in London are excellent. Clean and the drivers are superb. I'd take one anytime. I second the recommendation to take the Heathrow Express and catch a cab from there to your hotel. Sure, it's not the cheapest way to go, but after a long airplane flight, it's worth it to treat yourself to a fast train into London. We took the Heathrow Express each way from Heathrow and it was a no brainer, we didn't feel bad to spend the extra money to save time in transit.

I travel to London often and prefer taking the Heathrow Express to Paddington (simply a personal preference of time and convenience) and then tubing to where ever I am staying.
Please take the time to find out if the Express departs from your terminal before you arrive. The Express services Terminals 1,2, 3 and 5. If you are arriving at Terminal 4 you will need to board a free shuttle to the Express OR take the Heathrow Connect. At Paddington you can get your Oyster cards, a free and always helpful tube map and then take either the District or Circle tube line to St. Jame's Park station. Your hotel is about 6 blocks away. Lovely neighborhood. Yes cabs are great but why not get used to traveling via the London Underground. Enjoy your stay.