I have fruit (an apple, satsuma or celementine, watermelon etc), try to have fruit at least once a day.
I also love:
Muller lights (vary in cals depending on what flavour, I love the vanilla with choc sprinkles which is 86 cals or strawberry which is 102)
Walkers baked 99 cals
Special K mini breaks 99 cals
Crackers/crispbakes and ex light cheese spread (under 100 cals)
Weetabix oaty bars (the white choc ones are 67 cals)
Harvester cheweee bars 91 cals
Alpen light bars about 65 cals
2 finger Kit Kat 107 cals (great if you fancy a little chocolate!)
Mini milk 30 cals!
Have a look in the cracker/healthy eating isle in the supermarket, loads of different things you can have. All the supermarkets do their own low fat/low cal range and have loads of snack products in them, as well as the weight watchers brand.
Happy snacking!