well..... you could do it that way and the speakers will work but they're not really up to the job and im not sure its the best option.
Im not an expert and dont know a great deal about speakers but i have owned a sperates system before and i know the costs involved in setting one up, i wouldnt consider another seperates system unless i had a good sized budget.
Put it this way.... you can buy an all in one system now that has HDMI and optical in put for around £230 upwards (i mentioned the Samsung HT-TX35R) and just connect a HD player when ready or you can buy a £150 all in one then spend another £250+ for a lower end AV reciever

doesnt make a lot of sence to me but then its not my money.