Pastels and Spiders are excellent starting places because they are affordable, and they make lots of great combos.

You might consider getting a female morph if you can afford it. That will allow you to produce more morph offspring, and shorten the road to your combos. So, depending on your budget, you could do 1.0 pastel & 0.1 spider or vice versa. Or, you could do 1.1 pastel & 1.0 spider or vice versa if you can afford it.

But overall, the best recommendation is to go with what you like!