Hi Kpaske - Regarding subscriptions: There are subscription fees (very inexpensive though), it's far from just a DVR.
It will work without the subscription, but you need the subscription for it to find and record things for you. Without the subscription (program info) it wouldn't be the magical Tivo. It would be pretty useless, just a fancy VCR.
Joe - Thanks for the updated info on the standard Tivo, sorry I had some of it wrong.
I'm mostly familiar with the DirectTV-Tivo.
Regarding upgrades - Instead of buying a complete hard-drive upgrade kit, when I did my upgrade I bought a pretty cool cd with an image for my machine and the software to automatically make a tivo drive in a standard PC. It's called InstantCake, and you use it to "bake" a new Tivo drive. Really easy and cheap. Cost me $20 for the CD and the 160 gig Seagate cost $50 after a rebate so the total cost for my 150 hour upgrade was $70. Pretty good deal.
Also: The older Direct-Tivos have limits to upgrade size. The regular Tivos probably have limits as well. I think about 300 hours would be the limit on my Phillips unit.
The new LiteOn is the LVW-5005 (unless they have another one out now). To make it a little confusing Sam's has a special model #, only sold there, but as of a couple months ago I believe their model was the same as the older model (whatever model came before the 5005). The Sams model didn't have as many recording features, or the new easy guider menu system. Maybe this has changed in the last couple months since I got mine. I can't remember all the differences between the 5005 and the Sams model, but when I got mine I decided instead of getting it at Sam's, to spend just a little more and get the newer LVW-5005 at buy.com for $200.
Probably worth looking into and comparing the features based on what you will need to use it for.
Either way it's a great device, I've used it hundreds of times already and it's worked flawlessly. I can't believe how it records such high quality in real time.