Cnu,
VISA and mastercard are very widely accepted in Dubai but they are not as keen on AmEx and do not accept Diners Club. You have very little need for cash except to have some smaller notes available for tipping hotel porters etc. Service charge is included in all the restaurants so you are not expected to tip unless you want to single out someone for exceptional service. There is a large selection of restaurants with some of the best being in the hotels. A nice dinner for 2 cost about €100 with wine and soft drinks making up a good portion of the cost. We needed very little cash as we used credit cards for most things.
The city bus tour was about US$20 (The AED (Dirham) is at a fixed rate with the US$ so both currencies are accepted) which included pick up at the hotel, english speaking guide, entrance to the Dubai museum and a trip across Dubai Creek in a abra (a small wooden taxi boat) and drop back to the hotel. It was good value for money.
The dessert safari also included pick up and drop off at the hotel, a four wheel drive across the sand dunes, sand borading, a trip to a camel farm and a dessert bbq with belly dancing and other such entertainment. I think it was about $65.
As we were on honeymoon we splashed out a bit more on the hotel but there is a very large selection of hotels on sites such as and the Lonely Planet gives a large selection of hotels to suit all budgets(also gives very good recommendations for restaurants on all budgets). is a travel agent in Ireland that specialises in Dubai and
www.classicresorts.ie also has a good selection of accommodation.
www.escape2.ie also has some information on the tours available as well as accommodation.
Just to let you know there is a huge amount of constrution going on there at the minute, both buildings and roads. It didn't affect our holiday but just be aware that some hotels may have views of building sites and it can be quite noisey.
Hope this helps