I have a friend coming into town this evening for dinner, since I'm new to Luzern I was wondering if anyone had any great recommendations for a (semi) cheap and cheerful place to eat. Probably in the old town. Thanks in advance.

Hotel des Alps along the river close to Kappellbrücke for Swiss food and friendly service or Movenpick beside the Kantonal bank on Pillatusstrasse for more international offering. For great Thai try Cha Chas beside the Radisisson behind the KKL. All of these options are reasonably priced.

Why not go to the brewery:
http://www.rathausbrauerei.ch/

I always go when I'm in Luzern. The home brew is absolutely delicious, they have a lovely restaurant inside beside the large tanks and the food is really good. For food, you can either have a slap up Swiss/German meal or lighter snacks.

I like it. Plus it's right by the water.

Thanks guys much appreciated!

So where did you end up going Geordiegirl? Hope you had a nice meal.

We ate at the Brewery. It was lovely, thanks for the recommendation!
The food and venue were lovely, dining between the barrels is a nice touch, and it was reasonably priced for the location. I would definitely go again.

Great choice and am glad you enjoyed it. Can't wait to get back to enjoy a few pints.

Last time I was there there were some international students at the bar and it was great fun chatting to them.

Hey, I know this is a little late now but thought I would post a couple of places in-case you visit again.

The Felsenegg is great:

http://felsenegg-luzern.ch/

Off the beaten path and chilled out. I am a UK expat and have taken lots of friends there.

Alternatively, check out Opus:

http://www.restaurant-opus.ch/

Bit more in town and busier. When you reserve ask to be seated in the wine room/cellar, better atmosphere.

Both are on the pricey side but in these cases you get some great food in return (not always the case in Switzerland!).

Have fun.