[kmgroove]

If your not doing trivial applications like 37signals but rather more niche based applications it can be very hard to find areas to move into unless you have personal experience in that area. Most applications you see from startups are based around managment/collaboration/communication/helpdesk because although these are hard problems to solve it is fairly easy to become at least moderately knowledgeable in these spaces. There are TONS of needs for SaaS products, mostly to dethrone enterprise solutions. SaaS apps could exist for any level of business: accounting, procurement, logistics, managment, etc, etc. Building these and selling them can be very hard however. That is why people say build something for yourself. If you worked in procurement for 10 years I am sure you could make a great SaaS for it and solve many pain points, but you probably haven't.

If you don't have this experience well start asking people who do. There exist many niche blogs on enterprise software. Reading these will give the creative mind tons of ideas. Execution can be hard, and sales can be impossible though.

You say you don't want to up against 37signals, well look at it this way:

If you are going for the enterprise type apps the competition may suck, but it is there, big, and well entrenched.

If you are going for the 37signals type apps/helpdesk the competition is fierce and the apps are well made. You can compete because there is always room for a good product but you better be good.

When it comes to b2b if 37signals is your competition your not really in that bad a place. Many companies compete directly, and succeed in the space.

This all being said, I would look into analytic type software for improving sales/leads/conversions because there are many creative approaches yet to be uncovered and with apps like these the proof is in the pudding, and if the pudding tastes good people will buy.