I guess there are many ways to achieve the same ends, and not to disrespect anyone else's opinion, but here would be my advice. Forget about formulas that tell you how to allocate your budget. Find one product which you fall in love with which gives you some of the best sound you have ever heard in a system which you have heard. Next, try to match this product with other products which mate well with the first product, but permit you to stay within budget. Those formulas are usually manufacturer or retailer attempts to justify that you purchase some expensive but poorly performing product. There really is not a high correlation between price and quality in high end audio. There are a number of inexpensive products which perform superbly, as well as many outrageously expensive products which perform either miserably or without distinction. If you use your wallet to make your decision as to what amp to get, using some formula based on what speaker you have already bought, you will be doing yourself a disservice. After appearing to overspend on speakers, you might determine that you found an inexpensive amp which mates very well with your speakers and is an exceptional performer in its price range. In this way, you can recover overspending on one product with another while still keeping yourself within budget. Of course you have to be reasonable and keep you eye on the bottom line because if you spend 80% of your budget on an amplifier, it is going to be difficult to purchase high quality companion products with only 20% of your budget. However, other than common sense budget issues, if you liberate yourself from allocation formulas, I believe you will end up with a higher quality system, but still at, or close to, budget. I also believe that you can start your search for appropriate products anywhere in the chain. It is important to assure yourself of the capability of the component. In other words, can this product completely satisfy you musically in a good system? If it is not quirky (present problems to surrounding products such as impedance mismatch, highly inefficient speakers etc.) and doesn't blow the budget, then buy it and start there. Otherwise, you might want to continue looking. Good luck.