Don't buy ground spices (except turmeric). Buy cumin(and black cumin, also called onion seeds I think), mustard(yellow, red, black), coridaner, fenugreek (I'd forgive you for getting ground, this is a bugger to crush up), fennel - all seeds. Put them in a hot dry pan and toast them until you can hear them start to pop and crackle. Then transfer to a big pestle and mortar and grind them up until fine. Then add the turmeric. Every time I make a curry I use more spices. Go fucking crazy; the lovely thing about Indian curries is that you can just keep adding more flavours and it really works. For a 4 person curry I use something approaching half a cup of ground spices now.
That's an option, of course. I tried it a few years ago but ended up finding it too much for everyday cooking. I suppose my palate is probably not good enough to taste the difference all the time.
Part of the reason is freshness - ground spices go stale much faster than whole seeds, I think. And toasting them really wakes up the flavours.
Peckham people - you probably already know this - Khan's has an awesome selection of spices. Stock up there.
Don't buy ground spices (except turmeric). Buy cumin(and black cumin, also called onion seeds I think), mustard(yellow, red, black), coridaner, fenugreek (I'd forgive you for getting ground, this is a bugger to crush up), fennel - all seeds. Put them in a hot dry pan and toast them until you can hear them start to pop and crackle. Then transfer to a big pestle and mortar and grind them up until fine. Then add the turmeric. Every time I make a curry I use more spices. Go fucking crazy; the lovely thing about Indian curries is that you can just keep adding more flavours and it really works. For a 4 person curry I use something approaching half a cup of ground spices now.