Well, IPS is a specific type of LCD and LED is a way of backlighting an LCD. For example, my LG TV is an LED backlit (with local dimming) IPS LCD. IPS has superior off angle viewing angles to standard LCD. Off angle viewing has long been one of the weaknesses of LCD, and with IPS (which stands for In Plane Switching) technology, an IPS LCD TV would have similar viewing angles to an LCD. Now, in most picture quality measures OLED (of which SAMOLED is a specific type) are usually superior to an LCD. Some complain that colors are unnaturally vivid or are too cool (have a blueish hue). The Samsung Focus S is a good example of a SAMOLED that has the blue hue issue. The big disadvantage with OLED, at least at large screen sizes, is cost. LCD (even an IPS panel) are soooo much cheaper. On a 55" TV, you are talking like a $9,000 price difference. Now on a cell phone, obviously the price difference is no where near that extreme, I would imagine its still there. Personally, I love the deep blacks of an AMOLED, and I always have preferred Plasma to LCD (even though my current set is an LCD). On my Lumia 900, you can have a hard time seeing where the screen stops and the bezel begins, that's how black the blacks are. However, due to the blue tint, I preferred the Super LCD of the Titan to the OLED of the Focus S. Really, a large portion of it boils down to looking at the screens in person and picking which you like the look of best.
A note on LED backlighting. It is sort of a double edged sword. LED's enable what is called local dimming, which means your TV can selectively shut off the backlight in certain areas in order to produce deeper blacks, some times on par with Plasmas and OLEDs. This works best when you have a full array LED back light, which means there is a big panel of LEDs behind your screen. However, most LCDs that use LED backlighting are edge lit (including ever single thin LED TV you will ever see). This means there is a ring of LEDs around your screen instead of the backlight source being behind your LCD panel. This allows for a much, much thinner TV, but can result in unevenly lit images (the center will often be darker than the edges since it is further from the light). An Edge lit LED LCD can still use local dimming (as my TV does), but it isn't as effective as it is on a thicker, heavier full array LED panel.