I find accessories are especially important when you want to dress up a simple outfit, like a t-shirt and jeans. The hip-hop people do this especially well.
But you don't need a $75,000 diamond-encrusted, Jacob The Jeweler watch in order to pull it off. Some of Johnny Depp's beaded bracelets were made by his 4-year old daughter.
One of my favorite places in Toronto to pick up accessories are the kiosks on Queen (corner Peter), right between Lush and the Black Bull. One of the owners of the kiosks, Polo (shown below), is always enthusiastic to show me new, unique pieces.
Here are some pieces that I've picked up over the last year:
The silver finger brace (on the right), is especially unusual and a great topic of conversation at a club. If nothing else, an unusual or unique accessory is a great conversation starter.
One great source of accessories for me has been Butler and Wilson from London. I've ordered a bunch of stuff from their website http://www.butlerandwilson.co.uk/. The pieces shown below are stainless steel, not silver, and they are far from subtle. I can't count how many times people have commented on them (not to mention "borrowed" them for the evening) .
The one downside of the the company is that they don't seem to have nearly as many products for men as they do for women. Also, there doesn't seem to be that much of a diversity of designs. Skulls are cool, but a little overplayed.
Another cool brand is King Baby ( http://www.kingbabystudio.com/). They sell it at Holts though I've never bought any of the items. I think all the pieces are silver and they're not cheap either-- they range from few hundred dollars for the necklaces and about $1,000 for a bracelet.
By far the coolest bracelets I've seen were at Bergdorf Goodman in New York, on the Men's Third Floor. All pieces were silver and had real diamonds, so the pieces were several thousands of dollars, if not more. This will sound lame, but I don't recall the name of the label. But I think you can find cool accessories almost anywhere if you are on the lookout.
I suppose it's worth mentioning that there is a tackiness quotient when dealing with accessories.
Over the years, I've bought some pieces that, on second thought, just appear downright tacky, and I will therefore never wear them. Fellow Stylemountie Mariya thinks a thumb-ring is the tell-tale sign of a douche-bag, and that may be a good working rule of thumb (pardon the pun). I don't know if there are any hard and fast rules as to what constitutes tacky accessories. I guess we each have to find our own way.