Dear All! On 10th of December we plan to leave Amsterdam for Brugges (hotels are already reserved).
I am looking for online tickets for trains and buses, that could directly take us to Brugges (as we are with luggages). However, I have not succeed yet. Please help us with your advice!

I just bought tickets going the other direction, with a couple days gap between stops; Brussels to Bruges to Ghent to Antwerp to Amsterdam to Cologne to Brussels. My wife and I will also have our luggage and be gone for two weeks, but we pack light enough to change trains without much hassle. I am taking a Thayls fast train from Antwerp to Amsterdam, and smaller trains I booked on the SNBC Belgian Rail sight. I did a quick search on the SNBC sight and the best I could see was a Thayls train to Brussels, change at Brussels Midi, and train to Bruges.

I'm pretty confident you could find (possibly for a nominal fee) a luggage cart at Brussels Midi to get from one platform to the other. Since the large Intercity Trains (hence the name) will only go from city to city, I don't think you'll find anything going directly to Brugge. Can't speak on the buses, but think you will have the same problem.

Since you said "we" in your question, I think your best bet is to take the train to Brussels. When the train stops, one of you wait on the platform with the luggage while the other gets a cart.

http://www.bahn.de/i/view/GBR/en/index.shtml

The NShispeed website tells you what the train costs and gives you the opportunity to buy online.
A single ticket to Brugge from Amsterdam on 10 December will cost you €46.60pp

Alternatively buy your ticket at the international window at Amsterdam CS.

Eurolines buses will take you to Brugge for €12 - but it takes 6 hours.
www.Eurolines.nl

agendule: Thank You very much!
How much did it cost for you the trip from Antwerp-Amsterdam?
Thalys gives for 3 of us 111EURO price.

Many thanks!
bilboburgler: good website, however does not calculate the cost of the trip!
hetismij2: Thank You! We should now choose between cheap and fast options))

P.S. Are the views better by bus or by train?)

Sounds like the right price, I paid 74 Euro for two, 2nd class.