> select * from Table1
> where ((currency = 1) and (foreignvalue = 123.45)) or ((currency = 2)
> and (foreignvalue = 23.45)) ...

yes but with around 100 currencies it's will be an heavy query.
i was thinging to move this inside an UDF

ie:
where UFDConvert(Price, FromCurr, ToCurr) = xxx

not sure if it's the best