Hello Christos, or gheia sou, how you prefer :).

1. Mammillaria, without flowers not sure which one.
2. Looks like a Trichocereus, but not sure.
3. Guess it's a Mammillaria also.

Not much help, I believe, but wait the other's answer.

Rodica.

1. Might be Mammillaria carnea.

2. Don't know.

3. Not a Mammillaria. Look where the fruit are, that's a sure sign its something else. It looks for all the world like Thelocactus setispinus but with no hooked central.

Christos,
Plant number two is a beauty, excellent spination.
Want one of those for myself, here's hoping someone gives it a + I.D.
C'mon folks get the encyclopedias out!

I'm thinking Number 2 may be Trichocereus chilensis. See link below.

~Rosemarie

Here is a link that might be useful: Trichocereus chilensis

1 is a Mammillaria, 2 looks like a young Ferocactus, and I agree that 3 is an awful lot like Thelocactus setispinus.

All muy books are packed away at the moment while we're renovating, so I can't check any details...
I think #1 is one of the forms of Mamm. polythele, (possibly on of the ones found under old names such as M. kewensis or M. neophaecantha)?
At first glance I thought #2 was a Gymnocalycium, it could be as Rosemarie suggests, but I'm not convinced.
#3 I'm banking on Thelocactus setispinus

Thank you everyone for your effort. I am sure no1 is a mammillaria and everyone seems to agree on no3. Let´s see if there are more opinions

# 2 looks like a young Coleocephalocereus goebelianus.

Jordi

Ouch, Jordi, I never even heard of the genus but I definitely see the resemblance. Fingers crossed it gets lumped into something I can spell :)

Jordi,
You're absolutely spot on, #2 is what you say it is (beats writing it out)
Check the spination- the 4 protruding north, south, east, west spines with the "spiders legs" spines closer to the body of the plant
Check the link below.

Here is a link that might be useful: Coleocephalocereus goebelianus