<font color='#8D38C9'>You really do have to be careful buying from a non-authorized Etailer. Some companies, most notably Denon, will not honor the warranty if you buy from a dealer that isn't authorized. Is this a big deal? Could be, you never know. If I was buying a $200 CD player I'd probably chance it. But if I was buying a $1000 reciever, I'd be a little leery.
It also depends on the vendor. There are some mail order vendors and Etailers that will support the warranty themselves. The trick is to investigate how solid they are and if their track record is good. The BBB is one good indicator, as well as checking the sellers feedback (such as @ DealTime.com).
I have a lot of Denon gear, some bought online and some at a local dealer. Most of the time I've been fortunate to have good luck from both sources. Still, a year or so back I had problems with my Denon reciever, and I was dang glad to have local warranty service. But I also paid several hundred dollars more when I bought it.
Penny wise but pound foolish is certainly the way to put it. Unfortunately it's hard to really answer that one. Very few pieces of gear I've ever bought have needed servicing (the rec was taken out thru no fault of it's own...), so overall buying online is safe. But who knows, you could be the unlucky one.</font>