It's been years since I used one of them (you'll hear them called a closed-cell foam pad, or CCF.) A half inch is minimally warm; 3/4 inch is better - and the 1.5 inch is toasty. The go-to brand, for most people, is Thermarest (their Z-Lite or RidgeRest models are the standard.) As you learn more about ultralight packing, you'll also discover that you can use your sleeping pad to form the frame of your pack, which lets you use a lighter pack (and there are some patterns out there that let you sew your own pack, since you don't need a preformed plastic/metal frame to build it on.)
My CCF days are well behind me (but then, so is my youth and much of my hair.) I find I need a more cushiony pad if I want my hips to cooperate in a good night's sleep.
Self-inflating or blow-up insulated pads are more comfortable and more compact to carry. Some of the best "beginner" pads (and I use the term very, very loosely since I used one for about 20 years) are the Thermarest varieties (or the house-brand REI knockoffs, which look like they might be made by Thermarest.) They balance cost, comfort, warmth, weight, and durability about as well as any I've ever seen. If you suddenly inherit a fortune, you can drool over the NeoAir line they make.
My own preference, at least this week, is the Big Agnes Q-Core, which is decadently comfortable and not overly heavy. They're about to release an "SL" (superlight?) version that's half a pound lighter, which puts it in the same weight range as many of the Thermarest self-inflaters. (Lori - aren't you using this pad fairly often, too? Your review on Backpack Gear Test was what prompted me to look at it - that and the look of sheer bliss on the face of one of my buddies who had one.)
Probably the warmest pad out there is the Exped Downmat series, but they're overkill for where and when I camp, and a bit fussy to deal with since you have to pump them (your breath would wet out the down filling.)