A little help in narrowing down your budget / preferences will go a long way in providing strong advice.  Additionally, the size of your room is also important. 

A couple things, for surround, 5 or 7 speakers?  Do you like/prefer smaller more discrete speakers or would you want floor standing in front.  This potentially impacts whether you need a subwoofer.  Do you need 3D processing?  Is this a family room where you want to add a system for a bit of fun or is this a theatre room that will be calibrated for optimal sound.  For hardware, the range is dramatic.  Depending on how you define "decent" you could spend $1500 or you could spend $10,000 or $200,000. 

I personally have two home theare's, one 5 speaker system in a room that is not set up properly for viewing and it is there primarily to add a little fun if we are watching an action movie.  I have speng ~$1000 on it (excluding TV and DVD) and it sounds decent for what it is and other than a nicer speaker that would a be a little less tinny, I can see no point in upgrading because I can't make the room changes to improve the listening experience. 

The other is set up for proper viewing.  I have 7.1 lossless processing and the speakers are layed out in line with the specs from THX.  There is a "sweet spot" in the room and everything sounds better when you are sitting in that sweet spot.  I spent ~$7500 (ex TV & DVD) and it sounds great.  Most of the time, we prefer to watch movies in that room compared to going to a theatre. 

By telling us how you will use it and a rough buget, will help everyone offer guidance so you can begin demoing equipment.