post... other than, you may not want an external mic now - but if you ever do, not having the mic-in jack will limit any possibility of even trying that capability. Video is only part of the entire "system". As you already know, lighting is another part... editing is another part... audio is another part... 'nuff said.
The second part of your post deserves attention:
How do I play my videos on my PC? You need to transfer the video from the camcorder to the computer. Using an editor (XP SP2, I think, comes bundled with MovieMaker. It is entry level, but good enough to start with) you import the video. You can preview - or you can save and export the edited video back to the camcorder or as an .avi file on your computer... if you save it out to your camera, you can connect the camera to the TV for playback.
Do I need to transfer and save it using Firewire, or can I still play without saving? You will import from the camcorder to the computer using FireWire. Once the video is in your computer, the editor will have access to it. I don't understand the second half of the question.
How much disc space does a one hour min-Dv video take on PC drive? Standard definition video imported from the miniDV tape based camcorder to you computer's hard drive will use approximately 10 gig. It is strongly suggested that you use an external FireWire drive or add another internal drive to your computer for your video editing. It is not recommended to use the boot drive to store or edit your video.
I do not have a DVD writer, but I do have a CD writer on my PC. Can it be used to backup selected videos? It is strongly suggested that you get a DVD drive - either internal or external (connect via FireWire). Since you know the size of the files, here is some additional information: A CD can hold 700 megabytes. A single layer DVD can hold 4.7 gigabytes... nearly 7 times more data than the CD and a double layer DVD can hold 8.5 gig - nearly 11 time more than the CD - and nearly 2 times more than the single layer DVD. It is technically possible to use the CD as a backup mechanism - or to store very highly compressed (and much lesser quality than standard definition) video, but in practice, it is a very painful and time intensive activity. And you probabl won't be able to play that video back on a normal DVD player connected to your TV - and the video image you get when you play it back on your computer will be a very small screen size or very poor quality - or both.
Quick math... if a Single Layer DVD disc can hold 120 minutes of standard definition video in 4.5 gig, and the CD can hold only 700 meg... and we already know that the DVD holds a little less thatn 7 times more than the CD... then the CD only holds 1/7th... so 120 minutes/7 = ~17 minutes of standard definition video. The number is actually something less than that... likely closer to 15 minutes. This is not a good path to take and strongly discouraged.
If I'm recording 5 videos, can I remove video 3 from tape? Yes. Rewind or Forward the tape to the the place you want the video, then import from there... You don't need to import the whole tape just to get to the parts you want.
It is strongly suggested that once you shoot the tape, remove it from the camcorder, lock it, mark it using the labels that came in the tape case - and a Sharpie - and use another tape to record more video. Do not re-use the miniDV tape. At less than $3 each (I use the Sony Premium tapes), they are affordable enough to not re-use.
Other items:
No camera will be steady for long periods - say... longer than 2-3 minutes - when fully zoomed in on something and handheld. Use a tripod.
Learn to use the manual audio control - even if you don't use an external mic.
Learn to use the different lighting pre-sets on the camera... and even the white-balance feature.
Would be grateful if I can get help deciding between these.
I'm impressed with Panasonic's image stabilization at higher zoom in store. However, I'm not sure how it compares to Sony HC28 indoors, with say 40W wall mounted flourescent tube light. The video looked brown on LCD in store for Panasonic - is it still brown when recorded to tape? (I do have a reply from boya4 that the white balance may not be set, but this brown color was present only in Panasonic, not on Sony / Canon / JVC, so I post this again). I do hear that Sony gives better 'low-light' performance - though I didn't find much on indoors - I'm not exactly looking for night shooting outdoors - but indoors. Panasonic gives better outdoor performance, from the reviews.
Also, with a price difference of $90-$100 between Sony HC28 and HC48, is the HC48 really that much better with it's 1MP capability (not enough reviews on the video quality difference yet)? I'm not requiring still capability exactly - good quality video for 29" TV is more important.
I ruled out Canon ZR 800 etc due to reviews of high noise without external mic and bad low light / indoor performance, though I need a confirmation. I don't intend to use an external mic.
How do I play my videos on my PC? Do I need to transfer and save it using Firewire, or can I still play without saving? How much disc space does a one hour min-Dv video take on PC drive? I do not have a DVD writer, but I do have a CD writer on my PC. Can it be used to backup selected videos?
If I'm recording 5 videos, can I remove video 3 from tape?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic