Can anyone recommend me some ear plugs for sleeping?

There's a trick to inserting them. Right! Good mention, kidelo. I also put a little baby oil in my ear canals before inserting the plugs, too, to help them slide in as far as they can go. That has helped significantly. (It probably also helps to form a better seal between the plug and my skin.)

I had some custom made at a hearing aid place for only $75 CDN!

Most of the suggestions for earplugs here have been good, and have been things I've tried. Ultimately, I found little difference in sound-blocking between a lot of these choices, as the biggest issue for me, and probably for others is comfort and sleeping position. The softest foam ones are the most comfortable for me, as anything that sticks out or is firm becomes a problem when I sleep on my side. If you wear your current earplugs, put on isolating headphones over those, and wrap your head in a pillow, can you still hear the noise? If so, you may be dealing with a level of sound that is being transmitted through body or bed direct vibration. IANAAE (I Am Not An Audio Engineer), but that has been my experience; even with the most sound-blocking in place, sound will still get through somehow. What I also found was that continuous, steady noise was a lot easier to deal with than occasional, varied noise. Is that your issue in being kept awake? I think your best bet may be to combine earplugs with a steady source of noise, like a white noise generator that turns off after, say, an hour.

Frankly, the silicone earplugs have been the only ones that blocked out noise for me. I was camping out with a heavy snorer and didn't hear it AT ALL when I used those, and that's the first time I've ever not heard someone snoring in my vicinity. My experience with the foam ones has been the same as jessamyn's.

I like http://www.macksearplugs.com/ earplugs. I use them to swim too. They have worked for me for years. I have shared space with loud snorers and these keep me asleep. I take them when I travel too, you never know when you need them.

I'm a somewhat fussy sleeper and often sleep in ear plugs because they help me stay asleep, not just get to sleep. Basically most ear plugs are going to knock about 30 dB max off of the ambient noise. If you're in a situation where the ambient noise is either a lot louder than that, or spikes over that frequently, you're still going to hear stuff. I use http://www.audiocheck.net/earplugreviews_mackssafesound.php that you can buy in bulk at Home Depot and change them out when they get mungy or otherwise stop being effective. I find that keeping a fan running can also help a lot.

After trying tons of different ones, I picked up http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=320392150182&ssPageName=STRK:MEWAX:IT in a hospital and they're leagues ahead of the rest. In the summer I have an industrial fan right next to my bed and can barely hear it using these. I bought my last batch from the eBay seller above, so you shouldn't have any problems

I have the same issue with my roommates, and I actually use a fan as a white noise machine. For some reason, it blocks out noise better than anything else I've used. If it's cold in the room and you don't actually need a fan, then just turn it away from you.

My gf swears by Hearoes Xtreme (US product but http://www.amazon.co.uk/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=hearos+xtreme&x=0&y=0). However, she thought the best ones she's ever tried are ones I occasionally use – http://www.amazon.co.uk/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=bioears&x=0&y=0 – but they are reusable mouldable blobs of plasticky wax rather than foam. Once you get the technique of blocking your outer ear with them they are brilliant. I use them at festivals and can sleep through all sorts of racket.