Question: Right now, I use visual svn on my server, and have ankhsvn/tortoise on my personal machine. It works fine enough, and I don't have to change, but if I can see some benefits of using a DVCS, then I might give it a go.

However, if there's no point or difference using it without other people, then I won't bother. 

So again, I ask, are there any benefits to using a DVCS when you're the only developer?

Answer: 
Yes! I think the biggest benefit is the better branching + merging support offered by many DVCSes. Branching and merging is kind of a pain in the ass in SVN; it's annoying enough that it's not worth the time to create small, short-lived branches for quick feature additions, bug fixes, or experimentation, but merging is also annoying enough that it's a pain to create long-lived branches as well. On the other hand, branching and merging is a breeze in Git, so much so that I create a (local) branch for nearly every bug fix or feature I work on.

I think the tools offered by Git for visualizing repos, grepping logs, etc., are a lot better than in SVN, too (although that's more a Git thing than specific to a DVCS).

A DVCS also doesn't require a central server; when using SVN as a developer, you have to create a local repo to push into, which isn't a requirement with Git, since every repo contains the full history. As a corollary, archiving a repo is just a matter of zipping up your project -- there's no "central database" to back up.

I started using Git nearly four years ago, after using SVN for a while, and I haven't looked back.
Well, the default answer would be, "If (whatever you're using now) works for you, why would you change?".

But, yes, even if there is no reason for a change, I find using DVCS somewhat easier than the "older models". The following goes for *[Mercurial](http://mercurial.selenic.com/)*, which I use the most, so your mileage may vary, depending on which system you're going to use. 

* really easy to use - I figured out all the commands I need in an hour or so
* everything is local (you don't need the remote server to be online)
* very easy branching / merging - you don't even think about those things anymore
* easy cloning (also, a type of branching) - and generally, a much more user friendly interface (I found it more enjoyable than git's on windows; also some concepts are simpler; i.e. don't require thinking on my side, therefore leading to less fiddling with VS and more work done)
* works nice with svn

[Jumping gate to an intro to Mercurial](http://hginit.com/) and a [blog (pretty colours ;-) with useful tips](http://hgtip.com/).