Advice on AV Receiver versus Separates

Starting from scratch here guys on my first Home Theater. Any advice would be appreciated.

I picked up a Marantz AV7005 pre-amp receiver from Best Buy for $705 (open box). I can also probably pick up the MM7055 for about $800.

Is this combo a good option for a 5.1 setup?

Should I rather go for a receiver instead?

I have heard great things about the AV7005, but not as much about the MM7055. Are there other separate combinations I should be considering?

I would like to spend around $1.5k for the receiver / amp&preamp so I have enough left over for speakers, etc.

Thank you.