There's 3 adaptations/versions that I think are really good. Sadly, none of them can be viewed online for free at a good quality.

David Tennant's Hamlet (2009) can be watched on dailymotion in 10 parts (1, 2, 3, 4, 5, 6, 7, 8, 9, 10) and is really good. Tennant's acting is brilliant (which is no surprise) and although it doesn't make any extreme changes, it's a good way of taking the script and understanding what it might look like on stage. It can also be bought on Amazon here.

Mel Gibson's Hamlet (1990) is the one that I actually enjoyed the most. Gibson's acting is really good for a lot of the scenes where Hamlet is mad (or feigning it) and although the order is a bit muddled up, it sticks true to the script. It can be bought on Amazon here.

Kenneth Branagh's Hamlet (1996) is also really good and fun to watch. The ending, in particular, is a very interesting (modern) interpretation of the play. it can be found on Amazon here.

Hopefully that was roughly what you're looking for.