Apple macbook, solidstate H/drive option or not.

Would the way to go for music download , to order the macbook with solid state hard drive or just the standard one. I ask this as the solidstate has no moving parts, which offers a advantage , right ?

Yes, the solid state drive has no moving arts and saves on energy and heat as well as wear and tear, that said it's a fortune! I just bought the older model MacBook Air from MacMall for $1,149, for me, the 80G HD is enough for my laptop uses, I keep all my music on a separate HD on my main computer so when at home I can access it with the laptop if I want to. Either way, the 120 or 128 G HD is likely too small for a real music collection and you'll need an external drive. (my music collection is over 600Gs!)
there is a buffer after the hard sonic differences between solid state and spinning hard disk. use a dac with good jitter removal circuit. buy the biggest hard disk you can.
While I haven't seen any conclusive evidence either way, the users of SSD appear to indicate that the lack of a moving spindle decreases internal noise which somehow improves the playback despite the presence of a buffer. Whether this is accurate or not I'm not sure but once I get my Intel SSD later this month I'll put it to the test against my WD 1TB Green Power RAID1 array.
You might be interested in reading this:

Gordon Rankin recommends the SSD and has posted instructions on AA as to how to install one in a Mac Book.
Any good hard drive is pretty quiet these days - especially those designed for laptops. The average amp is going to generate more signal path noise than a spinning hard drive.

If you're worried about physical noise I suggest using a network storage device and stuffing it in a closet. You can get significantly bigger (and cheaper) space with that approach. I saw a 1 TB NAS drive for $220 the other day at Fry's electronics. At that price, buy two and use one as a backup.
We weren't referring to external noise.