Everyone knows the best thing about anything is the accessories. Whether you're buying gadgets to adorn your desk at work or shoes and a bag for a new outfit, accessories are always the most exciting bit. And sometimes they can spiral into obsession, of course - speaking as someone who has managed to get obsessed with plastic picks and sushi grass. The trouble with bento accessories, especially if you're a UK-bound bento obsessive, is that importing them can be pricey, plus not all of them are reusable.

Here are some of the bento cups I use regularly. On the left at the top are some really cute oval bento cups I bought in Japan. The trouble is when you use them, you never get to see the pattern inside, so I laid them all out and took a picture for posterity - which is on the left. You can also make out larger pink Hello Kitty bento cups in front. If you ever buy these from eBay or something, bear in mind they're from Daiso, which means they cost about 40p in Japan. Don't get cheated into paying a heap for them!
Oval bento cups are probably the shape I use the most, after the large plain white muffin cups at the bottom - more on those later. Unfortunately, oval is also the shape that's the trickiest to get your hands on as you definitely need purpose-made bento cups: oval cupcakes are fairly unusual! Like most bento cups, these are paper with a form of wax or plastic coating which stops food from leaking out - as long as you're not trying to fill it with soup or something. (Like you'd do such a thing...)
The foil containers in the top left were bought at Toko Lifestyle in Oriental City, Colindale, London. They came in several shapes; oval, square and round. Obviously I was obliged to buy all three - but they weren't cheap - around £1.75 per packet. The idea with these foil cups is that they won't catch on fire should you want to pop something in there and grill it. In Naomi Kijima's Bento Boxes book there's a recipe for a toasted broiled egg - that was the plan for these, but they are so flimsy I think they'd collapse under the weight of an egg. I'll report back if I'm ever brave enough to try it!
In the top right and bottom left of the picture you can see silicone cups - these are usually used for baking with, but are hugely handy for us British bentoers because they are reusable. The larger cups are sometimes too tall to fit in the bento, but I've heard you can cut them down to size with no problems. Being a bit of a snobby purist, I was initially reluctant to try these silicone cups, as I thought they weren't really 'authentic', but in Japan I saw plenty of these cups on sale specifically for use in the bento, so there you go!
Another set of reusable cups are pictured here too, the triangular, heart and square shaped plastic cups are fab and can squeeze in to tiny spaces. You can also add liquidy stuff in here too, which is helpful, and if you're worried about juices leaking and staining your bento I'd definitely recommend them (I used mine for the hijiki seaweed recipe as I didn't fancy black stains everywhere - although it didn't seem to stain in the end anyway...) The downside with these is of course that they can't be squashed to fit the available space like paper or silicone cups.
Finally, the cupcake cups. You can pick these up from most large supermarkets in the UK, and if you're starting out making bentos and still waiting for all your lovely goodies to arrive, use these! I've got a range of sizes, muffin, cupcakes and mini cupcakes, all of them are useful for something. I've used the tiny foil backed ones to store mayonnaise - as long as you don't shake everything around they're pretty good. Plus, you can use as many as you like and never feel guilty over the cost! Downside - not as cute as Japanese ones, but I can live with that when the Japanese ones cost £2.50 a packet from eBay...
The cool mosaic image was created by fd's Flickr Toys.