The fog lamps are an absolute must in my opinion. They provide the following advantages
1. Better view of the road along with low beam at night , particularly on single roads where you dont want to use the high beam due to oncoming traffic.
2. Makes your car more visible to oncoming vehicles during fog or rain.
3. Life saver , if headlights suddenly stop working.
4. Improves looks, rather than having empty "slots" on your bumper.
LED fog lamps are also available , which you can use as DRL i guess.