Gas prices do not affect(effect? SB, help?) how often I fill up or how much I drive.
Maybe if the price doubled I would drive less, doubt it though.
Do they have any effect on how much you purchase other goods or invest?
Not really, If i want to buy something but all of a sudden its $2 more expensive because gas prices went up I'm not going to say "Welp, that flatscreen is $2 more than it was last week, guess I wont buy it anymore"
That's not exactly what I meant. The goods are more expensive because of gas prices, but you are also $30-$50 (maybe even $100

) poorer every month because you are spending that money on gas instead of luxuries. Some people spend less. Others save less. Poors lose their house.
Gas prices should concern us, but I don't think they are so high that they are causing major problems. Like I said, though, I walk to work and don't drive very much, so I'm not even sure where the prices are right now.