I use duplicate external HDs for my storage, mirrored nightly using SyncBack (which I heartily recommend – inexpensive, easy to use and comprehensive).
I would recommend against LaCie drives, actually. I have owned one and had it fail on me within two weeks and have heard similar stories from several people.
The other thing is that many LaCie external drives are actually two drives (if it’s a bigger enclosure that you would expect for a single drive, this is the case). You might think this is a good thing – redundancy etc., but it’s actually very bad. The two drives are a simple concatenation – so for example a 600GB drive is two 300s stuck onto each other. This means that it is twice as likely to fail, and a failure of one drive will bring the whole volume down.
As far as archival DVDs, I don’t do them because (a) it’s time consuming, (b) the burning process is fickle and has a habit of failing often, and (c) no-one knows how well DVDs will stand up to aging. I don’t want my hole card in terms of data storage to be something of which I can’t be 100% confident.
For my offsite backups I have just arranged space with my hosting company for a couple of USB drives attached to my webserver, and they will be my insurance against my home/studio burning down. If you don’t have such an option, buy a spare drive and keep it at your brother’s/sister’s/friend’s/in-laws’ house and just dump your images to it once a month or so.