Hi:
First off I have been searching and reading for several days and the more I learn, the more different directions I keep getting pulled in. This is about the most jazzed I have been about audio/video in a long time.
So I just moved and I casually decided to look into HTPC's after a friend told me he was streaming from Netflix, cause maybe I can forego cable for a while. I bought a used HP media center M7750N locally and am awaiting my 3Meg/sec DSL connection this week and an HD 4650 vid card I got for the new PC. I will be connecting to my PC, coming out HDMI to a Denon AVR 2808, then on to a 50" HD capable Sony Wega.

The HTPC has the AMD 5000+ dual processors. It is running Vista Home Premium. It has 2G ram which I am upgrading to 3G, I got the remote for media center, wireless key/mouse, a factory installed tuner card plus an aftermarket All in Wonder 650 card, and a remote to hook up a set top box. I have no ps3 or xbox.

My question here is even though I'm not on line here till Wed or Thurs of this week, I know my friend is streaming Netflix and now Hulu since I told him about it direct from his PC to his TV, so I'm sure I could do the same. The question is what are the advantages of say the Roku box? Or some of the software being sold by people like themediamall? Basically what benefits do the Roku, or the software bring me? Are there implications with the ability to capture or record streaming content to my hard drive? That is the feeling I am getting as to what would be different, but I am not entirely certain.
Sorry for the long post, but I wanted to try to be as clear with my system and question as possible.
Thanx for your time and answers in advance.

The new vmcNetflix plugin for Vista Media Center allows for the recording of the stream... this will turn out to be a fairly important feature for you - and you're probably not going to like this, but the top quality from Netflix is 3.3mb. So you're going to be able to stream the medium quality, which is not horrid, but it isn't anywhere near DVD quality. Monday night, my wife and I sat down and watched a Netflix live stream, but we have a 12mbit fiber connection so we get that top stream quality. We watch on our projector with a 100" screen - we actually watched it on the Xbox 360 (as an extender) which connects through the VMC computer in the den.

You will want to "record" the stream at the highest bit rate and then playback at your leisure. You will most likely look into ripping discs and storing them on the PC because you'll prefer the quality. Bluray drives are under $150 now, so that addition will prove to be a worth the money.

I don't think PlayOn (from themediamall) would do you any good. It's more about streaming from the PC to a device hooked up to your TV, like the PS3 or XBOX or other thing that will pick up a media server).

If you're building a HTPC, you can just watch HULU or Netflix directly. PlayOn is more geared towards those people who don't have a PC hooked up to the TV but want to stream from a PC to another device that is hooked up to the TV.

Thanx for the answers.
I think I understand now, so I have no real need for the Roku box, for the same reason I have no need for playon; because I will be using the HTPC as the source.
Yeah, I am aware that my 3mb connection will not net me the higher quality. I live in an area where there is quite a bit of fios availability, but it is not available in the condo complex where I am renting so I went with the Verizon DSL pack hoping I will see fios become available sometime in the fututre. Of course it could just be the condo has elected not to bring it in. Comcast is available, but I was unimpressed with the prices they were offering. I think they only offerred 4 months at the new subscriber rate, then it was gonna jump to ike $52/mo for 6mb, and that was just a bit on the pricy side for the bandwidth I thought. Part of that is because I won't bundle my phone (don't want a landline) and I'm not really interested in their cable offering.
I'm tired of paying gobs of money to get 100+ channels so I can watch the 8 or 10 I actually like. If HBO ever breaks away from the nazi cable companies and offers their service direct I would never speak to a cable provider again LOL.

I hear ya. I pay my $85 DirecTv bill every month, yet I have so much other content available on my TV....Hulu, Netflix, Playstation Network (PSN), XBOX Marketplace, etc. And now that PlayOn is doing Hulu in 480p (which looks pretty decent) I wonder if it's really worth what I'm paying for DirecTv. Giving up HD would seem like a big step backwards, but I'd also be giving up all those animated bugs and snipes advertising other shows. I watched Fringe on Hulu the other day and it was so nice to not have crap popping up on the screen every few minutes....granted it wasn't HD, but it certainly was less annoying.

Arrrg. I hear you on all that advertising. There is nothing more annoying than watching a show you are really enjoying and one of those adds pops up on the bottom with people jumping about and walking across the bottom of the screen. For now I will so enjoy not dealing with that. Unfortunately as streming grows and developes enough of an audience, the advestisers will scream for their space amidst it all on streaming as well. That is my love of HBO. Solid entertaining series with no commercials or adds during the show.
It is also the reason I have taken to building a DVD collection over the last year or so. Good video and audio quality with no advetising.
I wish the networks knew how often I decided to never use a product because it was shoved down my throat while I was just trying to relax with some entertainment and get away from the world for an hour or two.