Out of all the electives one could take at Hogwarts, I would go for Arithmancy and Muggle Studies. Arithmancy always appealed to me because it works a lot with numbers, which I love working with :D I would want to take Muggle Studies because it seems like it would be... easy - what a good reason to take it :P Muggle studies and Arithmancy both seem like fun classes that would give me a break from my usual studies. I would take them both up to NEWT level because they could prove to be helpful when I go into a career, since I would know a lot of mathematics and I would be familiar with the muggle's world. When you think about it, Hogwarts doesn't teach too much about mathematics, which is an important skill to have that proves useful every day.
While Hogwarts does teach Ancient Runes, there really should be classes on normal languages. We see foreign language classes taught in Muggle schools, but not in Wizarding schools. Students end up not learning other languages that they can use in day to day life.
