Budget would be $150 ( used or new).

My amp is Hughes and Kettner Attax 40 ss amp

Right now im considering Boss Me 25, digitech rp355, vox tone lab, and some others.

What should i go for any why?

sɹǝʇndɯoɔ ɥʇıʍ poob ʇou ɯı uʍop ǝpısdn sıɥʇ sı ʎɥʍ pob ɥo
Well I have the RP500, and I think it's pretty wicked. If you can save enough money for it, then I think you should definitely consider it. It's a neat device.
Marshall amplifiers are the truest purveyors of rock and roll known to man.

"And give a man an amplifier and a synthesizer, and he doesn't become whoever, you know. He doesn't become us."

Holy crap, check this out!
out of those, the tonelab. If you never want to get another multifx unit ever again besides whatever you plan on getting, then the TC Electronics G Major.