What do you mean by a decent site? I think building a functional, mostly text based site with a few MP3's and a paypal account would be a piece of piss as long as you kept it basic and didn't go overboard with Flash animations, etc. If you really care about getting your musict out there, then I don't see learning a bit of HTML or Frontpage as a huge struggle.
Well, I tried this, a few years ago. I had a great idea for an online techno label putting out the music of me and a few others. I couldnt get a distribution deal, so the website was critical to the whole concept; it was the label's window on the world. And I just found that implementing it was an absolute nightmare. I spent ages reading about HTML, trying to learn dreamweaver, troubleshooting technical problems, etc, until it was affecting both the quality & quantity of my music. When I took my plan for an online shop to friends & contacts who work in web design, hoping to cadge some favours, I was told to forget it: it was several grand's worth of work, even at mate's rates. Even with a drastically cut down site plan, I still managed to piss off some good friends with my badgering - and without the online shop, it was pointless to be honest. The whole experience was extremely hard.
Like you say, you can just keep it basic - but then there's nothing to raise you above the background noise of the 'net, so your site is invisible. For it to work, it needs to be both an engaging visual representation of your aesthetic and a slick facilitator of any transactions that take place on-site. There are some musicians who have the skills to build a site like that without taking away from thier music, and good luck to them, but if you set that as the bar that every musician has to get over in order to have a web presence, lots & lots of people will fail. I'm pretty technical - I'm studying engineering, I make techno on a PC, I use software like Reaktor that's complex by any standards - so if I can't do it, the vast majority of musicians will be stumped without outside help.
This can be expanded into a critique of the DIY aesthetic as a whole (OT but bear with me, this
is going somewhere). DIY artists are expected to master promotion, marketing, manufacturing, technical support, accounting and networking, with no regard to their actual ability in those fields, in addition to making the music in the first place, and holding down a straight job if it doesnt pay the bills. With the decline of indie labels and general fragmentation of the underground music scene, this one-man-band approach seems to have become the norm for emerging artists but in most cases I think it just cripples them as musicians. What's more, it allows major labels to lower their risk exposure by signing artists further down the path, once some kind of audience is already in place - and often when the artist is so exhausted from running the show on thier own, and so desperate to get shot of this workload, that they'll sign up to deals that they wouldnt normally have touched with a bargepole. PR, accounting, networking etc are difficult, time-consuming and, to be frank, dull - that's why there are highly paid professionals in each of those fields.
Some artists like Fugazi are capable of operating independently for years and years, and their music is unaffected (often feeds off it in fact), but if that's the level of commitment that's
required to operate then a lot of musicians will just not bother, and that damages underground music as a whole. Musicians need infrastructure - that's what has been lacking over the last decade, and (party) why music is currently in such a state. If the underground isnt capable of building it's own then it must co-opt the structures built by others - probably people, like Rupert Murdoch, that you wouldn't really want to share a pint with.
This argument about using the enemy's tools is as old as revolutionary politics itself - it's the central dilemma of the RIU&SA era, and it's recurring here in a different form. There's no right or wrong answer because each person needs to decide for themselves where they draw the line, and where refusal to use a particular service becomes self-defeating. If people don't want to use myspace because Murdoch owns it then I respect that, but if you're waiting for a service with a reach and power comparable to myspace that's totally untainted by the hand of global kapital.. I'm sorry, but I think you'll be waiting a long, long time.