.. for quickly now ? .. we could mostly recommend the Koma Kommander, making sense for nearly everybody who is involved in what we do as long as he/she does not have it already (?).  If this is too much, you can just learn a bit about it with a great (german) book called Das grosse Buch zum A-100.
If it should be a bit more, there are several monophonic synths in stock like the Magma, Mono Lancets and the Moog Minitaur, if a synth is not it, the analogue Moog Delay in its latest version as a very good tool and .. if you really dont know, just call us or step in with the story of your love and we will find something to make you happy.