What a great question!
Let's see...
Favorite services:
*Anything design related (business cards, websites, newsletters)
*Consultation (small business development, internet impact, marketing,
SEO, website development etc.)
I honestly haven't had any requests in the past few years for anything I really dislike. Though early on there was one short-term client who wanted to me to go around to all of the job listing websites and gather specific information from a certain type of listing. It was *endless* and had no room for creativity in any direction - I had to approach it a specific way...that one was hard

The repetetive, always ongoing things can get tedious but there are also times I really appreciate those kinds of tasks...
My most commonly requested services (by new clients) are:
*Newsletter management (custom template design, content editing/creation, mailing list setup, account management, etc.)
*Research (various industries, purposes, etc.)
*Website overhauls/updates/additions
*
SEO consultation/implementation (both on the website itself and off)
*
PR and media (public relations, press releases, media relations, making contacts/connections with specific media segments)
What are you anticipating will be your own favorites and least favorites?