Are there easier ways to upgrade (modules & themes)?

I have been using Drupal since version 4.5.x.

I run a few sites on different domains (and some multiple sites on a single domain, single database). I implement a many contributed modules and themes.

I recently upgraded some of these sites to drupal 5.1. The experience was tiring... although satisfactory at the end. The reason for the tiresome process is downloading, expanding, uploading the many modules & themes. Before doing so, i go through the usual prepping - by setting my drupal site to vanilla mode before uploading the new site and modules. then, i would activate module by module - and if required update the mySQL databases.

Is there a simpler and better way of doing so?