[quote name='seen']Netbooks are really underpowered machines.
That being said, I owned a Dell Mini 12 for a short period of time. While it is a light machine with a near full-size keyboard it suffers from a slow 4200rpm pata hd. Also, the Atom processor is
quite weak in terms of multi-tasking. I no longer have the computer as I felt it didn't meet my needs to replace my laptop.
What is your budget for this, do you want to upgrade it at all or have a good machine right out of the box?[/QUOTE]
See, that's your problem right there. Netbooks are not and never were meant to replace laptops or desktops. They were meant to be inexpensive, ultraportable machines that were just fast enough to get you by on the go, and compliment your more powerful but less portable hardware. Typically, many people only do light computing when on the go and thus the lower specs of the netbook are more than plenty when they just want to sit in a coffee shop and fool around on the web or check their email or do facebook or whatever. If you think you are supposed to be able to edit photos, play games, etc. on a netbook then you don't get the point.
This, sadly, is also probably why it is not likely you will see a netbook from Apple. They are not interested in playing the low margins game with other netbook manufacturers, and to make one that is sufficiently "apple", it would probably have to be much more expensive than the competition, thus defeating the purpose of a netbook and probably making it not sell well. It would probably turn out to be like the macbook air, only a little less extreme in terms of price. Be advised though that I would love to eat my words on this one, cause if apple did release a pretty cheap really small notebook I would be severely tempted to buy. And for no real good reason either

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That said, I don't think it would be wise for the OP to replace a macbook with a netbook, as they would probably find the computer too slow to use as a primary computer.
One thing I have been really tempted to try is to get one of those Dell Mini9s, and install OS X on it. The hardware inside the Mini9 works well on OS X so I hear, so putting OS X on it is little more than simply copying the install DVD to a HD or USB drive and doing a little messing around with boot sectors or something. Then, everything pretty much works as it should. Video camera, bluetooth, etc. The low price for this makes it pretty tempting and the Mini9 looks like a fun size, but I think ultimately the low screen res would be too limiting for me- plus if I really sit down to think about it I wouldn't really use the netbook much other than novelty factor. I don't go to coffee shops, don't use facebook, etc.
Ruahrc