I Am The Ant wrote:A few people have told me that it's best to have two sleeping bags - one for the summer, and another for the winter, because as you mentioned, it can get quite hot using a cold weather bag in the summer months.
This can be an issue, but is easily overcome with a single warm sleeping bag by leaving the zip open part or all the way. I have a very warm sleeping bag, and on most summer trips, I leave the zip fully open, and use it more like a doona (even though it's a mummy shape). Note that there are some bags (some ultra-light ones) which don't work as well this way, because the zips only open half way down the bag. My next bag (hopefully next week) will be a semi-rectangular shape. Even though they're a tad heavier, and not quite as warm (for their weight), I think it will suit me better as the mummy bags are too restrictive for a restless sleeper like me.
What kind of brands do you recommend personally? I've used Katmandu gear before - not sleeping bags, but other gear - and quite liked their stuff, but I have no clue on any of the others. As you can probably tell, I'm totally green when it comes to camping out and the like.
I've got a J&H Winterlite (J&H are now 'One Planet') which has finally got a big rip down the side after about 20 years of good use (fabric got caught in the zip and I pulled hard and the 20 year old fabric gave way - down everywhere!). My next bag (currently on order) will be a One Planet Zephyr 700 (if I like it when I try it in the shop). One Planet are not cheap, but they're good quality and are an Australian company (most of their products are either made or partially made in Australia).
I think Katmandu bags would be fine, but I'm really not familiar with them (I'm sure others here can comment on that). However, make sure you wait for one of their sales (which come along frequently), as that will bring the prices down to something realistic.

I believe that MacPac and Mountain Designs also have good bags, but I've not used them myself.
I'm sure any well-known brand would be good, so it's really just up to the features you want. Eg, does it need to be completely waterproof? rectanglular, semi-rectangular, mummy shape? 2d or 3d hood? Slot for sliding in a sleeping mat? hood slot for stuffing in pillow/jumpers/etc?
Personally I don't need any of these features and just need to choose my preferred shape, and temperature rating, and then get something that's light weight and in my price range.