which card in Hong Kong to use can you recommend?

Well, first of all, one Octopus Card can only be used by one person. So you need two cards. According to your situation, you are suggested to buy the Round-Trip Airport Express Travel Pass.

It contains two Airport Express single journeys plus 3 consecutive days of unlimited travel on MTR (except East Rail Line First Class, Lo Wu and Lok Ma Chau stations), Light Rail and MTR Bus (Northwest New Territories).
It costs HK$350 (with HK$50 refundable deposit). :)

thank you for your reply. so does it mean that we only need 1 airport express travel pass card for our daily transpo instead of the octopus card? what's the best option for transpo from airport to our hotel and also for the rest of our trip? bus or mtr or taxi?

No, the Airport Express Travel Pass is also a kind of Octopus Card. So you need to purchase two.
After purchasing it, you don't need to buy other octopus card.
This pass contains one or two AE journeys. So you can take AE to downtown area. And then transfer to free shuttle bus or MTR to the hotel. You can use the AE card tot take metro for the first three days. But to take city bus and ferry and the metro on the fourth and the following days, you need to load some extra money into it.

sorry but im still confused. sorry for asking so many questions. they say this airport express travel pass cost is 220 HKD. why is it now its 350 HKD? what's the difference? and also from airport, if we're going to have this AE travel pass card, are we going to ride a train or MTR? if its a train coming from the airport to mong kok, where is our drop off point? do we still need to ride a bus after this? our choice of hotel will be situated somewhere in nathan road near the Sino Center.

Oh, the price increases recently, 250HKD and 350HKD respectively for one and two journeys on Airport Express. You are going to take Airport Express Train to Kowloon Station, and then transfer to a free shuttle bus to your hotel. :)

thanks again for the reply. so there's a free shuttle bus from kowloon station to any hotel in nathan road included in the airport express card?! where is this free shuttle bus located in the kowloon station? and also is the airport express train a 24 hrs. service? same goes with this free shuttle bus? because our arrival in HK is at 9:30PM.