I've gone and introduced Blogger comments after all. The biggest advantage is that there is no size limit. Also, old Haloscan comments disappear after four months, which is really annoying.
I've copied across any conversations I thought were particularly worth saving (so you'll see a few posts with "1 comment" which is actually several old ones put together).
In other news, the template saw some minor tweaking (hopefully the links look a bit better now - that grey hover background was awfully ugly).
I've also introduced Blogger's new "email this post" feature - that's the little envelope you should see next to the permalink at the bottom of each post. If you click on it, you can quickly and easily email the link of that post to a friend (e.g. if you think it might be of interest to them).
Lastly, you can use the search bar at the top of the page to search this site for key words.
Update: You may notice that some of my older posts do not have Blogger comments enabled on them. Unfortunately, there is no way for me to fix them all at once. However, I can introduce the comments feature to the posts one at a time. So if there is an old post you wish to comment on, simply send me an email with the link of the post, and the request "please enable comments on this post", and I will do so. You may find the new "email this post" feature to be convenient for this purpose. My email address is described on the sidebar.