purchasing a used powerbook g4(aluminum)

These go for relatively cheap on ebay(last generation as well) about $350 and under(USD). I am thinking of purchasing one for basic uses such as IMing, Office, watching movies on the go, and internet browsing. I am an intermediate OS X user with a ton of experience, but I haven't used it in a long time. I love the operating system, and with a 15" screen, I believe this is a much better buy than the eeePCs at this price with Linux or XP.
The majority of systems include 1GB ram and 80gb hard drives, but those aren't even a concern as I have ran OS X with 512MB ram with no problem in the past(although it was on a macbook with a core duo...). The hard drive is no problem as I have a 2TB network drive I can use. I would really like to make this purchase, I am just worried if something breaks I will have too many issues. Although the only thing I am really worried about is the battery breaking, I am hoping that can be replaced easily too.
I am just rambling now though.

what is the processor speed of that G4, that is the only thing that would hinder the easy use of movies on hat system

1.5GHz

^ Sure. 1.5GHz is as good as new. Its faster than those Atom CPUs that Netbooks use. ****, 1.5GHz G4 will pull through almost any task you throw at it.

Even I would love to buy one of those, I doubt you get them for 350$ so easily. At least refurb sellers dont give those kinda prices.

It might be because its on ebay as a used product and not a refurb seller. the only thing I'm not sure about is how people are saying their logic boards and stuff are dying on them. makes me kinda nervous as i can't get an APP or anything

No worries with Logic board on one of these. I'm typing on one I bought from eBay a month ago right now. It's absolutely fine. It runs Leopard no problem and is fast enough for most video etc. I have been using Logic 7 no problem too.
I have 1.25 g of ram though which helps.
If you get one that cheap don't tell me, I paid £400 (with a spare battery and a case, and it's immaculate).
It's nearly as fast as my new iMac!

powerbooks are not the ones you need to worry about the logic board it is ibook g4 i have seen many of them and only one was good.