First and foremost if you don't own a TV that supports 720p support I can't advice the PS3 until they fix their scaler, or add a must have title. Speaking of scalers, if you plan on using the PS3 to play your PS1 PS2 games don't, with one exception discussed later. The scaler is horrible, and until they release an update through a firmware patch only your progressive scan games (Shadows of the Collousus for example) will look remotly good on it. The one exception would be if you own a Samsung DLP with game mode. Game mode makes them passable but they still look better on a PS2 with game mode on. Please note that game mode was made for 480i games and will make your 720p/1080i/p games look off.
Also, if you don't own a reciever with DTS, Dolby Digital, and or PCM via HDMI you will be shorting yourself on the audio of all the movies, and most games.
Buying the system:
Wait until either Bestbuy has a 10-20% off any purchase coupon, or what I did was open a target card and got 10% off, plus another $35 thanks to a local promotion in store. Do not waste your time with the 20gb model unless you have a spare 2.5 serial ata 120gig drive under 5200rpm laying around . You are still shorting yourself wifi and the card reader though.
If you do own an HDTV with HDMI (or DVI) by all means use it. Just for the love of god don't buy retail cables. Look online, and remember digital cables work or they don't. Analog is a diffrent story though. I would just stick with the official Sony Brand Component cables (the same from the PS2) and would avoid Mad Catz cables. I have had bad luck with them in the past. Also, please remember HDMI is for content protection (HDCP). It is difficult to tell the diffrence between a good component feed and a good HDMI feed at the same resolution.
Set your resolution to either 720p or 1080p. If you do not games like Resistance will default to 480 which defeats the purpose of a higher resolution.
I do not own an HDMI reciever so I can not comment on running the audio and video through that. However, if you have optical outputs on your reciever use that. Once again optical is a digital connection so don't overpay on the cable! If you don't have an optical option just run the audio either through the HDMI or the component stereo.
Any cheap wireless keyboard/mouse combo that hooks up via USB. This is a lifesaver for putting linux on your system.
I would also recomend that you own a DVD burner for putting Linux on your PS3.
The setup is usually easy, but if you get a blank screen through HDMI like I did plug in your AV cable and set it up through that; than turn on HDMI. Set the video/audio to your systems specs (eg I have it set at 1080p video with optical audio with DTS and Dolby 5.1)
Once you have your main account set up, go back and create a second main account in Hong Kong so you have access to the Asian playstation store. I wish I had the name of who gave me this tip, but when buying games from the Hong Kong market you need to buy them in increments. So if you wanted to buy Tekken 5 DR for the PS3 for $125 HK ($16.09 US) you would need to put 2 $40 HK credits in your cart than purshase the remaining $45 when you download the game.
You do not have to be in your HK account to play HK downloadable content
Unrelated but if you are running Dark Alex's 3.02b custom firmware on the PSP I highly recomend downloading Hot Shots Golf 2 for the PSP from the Sony Store since it allows you to play ANY PSone game on the PSP with very little effort.
I am taking my wife out to a movie and dinner; depending on the interest I'll post how to put linux on the PS3. As well as current limitations to the PPC version of Linux on the PS3.