When starting to get in to AV its always worth thinking about what you want to achieve. Do you want atmos and have you got a suitable layout for it. Whats the maximum setup you can accommodate? How loud will you be listening (important for power requirements). Do you want it for stereo music playback, if so what sources (cd, turntable etc) will you be using?
The sony amp seems to get good reviews, but cant see much on the speakers. For the amp it has no preouts so if you find it lacking powerwise, you can't add any external amps, nor can you integrate a stereo amp (this is important if you want to have decent stereo as well as a surround system). The more speakers you have the more power you need, hence the ability to add extra amplification is always handy.
Agree with
@Thaedolus about packages. I would be looking for speakers from dedicated speaker manufacturers (US has a lot of very good options). For a sub, these can be from a different brand, but I would be looking at a specialised brand, e.g. for US, SVS are very highly regarded (also their speakers), monoprice subs are also excellent.
At the end of the day, it all boils down to what your end goal is. If you just want a simple surround setup with minimal fuss and low costs then a package will work, but will it give you a better system than finding better speakers and sub separately, very unlikely. I would try and find an independent dealer and build a package with them, as you will be able to mix and match and try and get a deal. Also if they are local you will be able to hear it, whilst also be able to ask them questions.
Before you do anything it might be worth having a read on avs forums (it is US based), as they have a wealth of knowledge and they will be able to provide guidance/help.
