1. buy the most expensive hardware on the list first (the panel).
2. buy an NMT with TBs of storage
3. buy a mid level receiver and an updated one. it is harder to re-sell an outdated entry level recievers at a good price than a second hand speakers.
3.1. if budget is a concern go for a good 3 speaker set (fronts and center) first rather than going for a cheaper 5 set speaker which is not so good and will not match you mid level receiver.
4. the sub completes the HT experience. the .1
the subs will change everything so go for a good sub. you may think subwoofers are expensive but it plays a critical part in HT.
5. get good speaker cables, not expensive (or very expensive) but good thick speaker cables.