Just to elaborate on what Ghost said (especially since my build thread doesn't really show the progression, so it's tough to understand if you haven't been following the process)...
I didn't really have a goal in mind when I started modding my rig. My only priorities in the beginning were keeping it "street-able" enough to be a good DD for my commute, and making sure it was rugged enough to tackle back roads when I was storm chasing or photographing wildfires on the weekends.
I started with a super cheap eBay special lift kit that consisted of a rear shackle and front spacer. It gave me a nicer stance (about 1.5" of lift in the rear and 2" in the front), but it rode like crap on stock shocks/coils at that height, and looked really goofy with stock 31" street tires. So I soon upgraded all the way around to Bilstein 5100s that I purchased used from another member on the forum, and then sold my stock tires and upgraded to 32" Goodyear Duratracs (265 75 16). I went with a 32" because, again, I was trying to stick with a modest approach to keep the vehicle as economical as possible for commuting (cheaper to replace, better MPG, etc). I ran the rig like this for quite a while and went on several trips with the group.
I started to realize that I really loved the overland style of offroading, and developed a vision of how I wanted my rig to be. I really wanted a serious overlanding rig that was set up to spend multiple days at a time in the desert or mountains. Since then, I've slowly upgraded more and more, mostly waiting until I came into a good deal on something, or waiting until I had an absolute need for what I was going to buy (such as buying my ARB fridge once I had plans to spend nearly a week in Death Valley). I purchased a pair of UCAs that someone was selling for cheap, and kept them in my garage until I had enough money to buy some new Radflo 2.0 coilovers and PRG rear shackles. More recently, I purchased a set of used Radflo 2.5" coilovers and sold off my 2.0s. Every time I've upgraded, I've pulled off the existing components and either gave them away, or sold them on the cheap to someone else that was starting out or upgrading, since this is the same way I've acquired many of my parts as well.
So as John said - if you have an idea what kind of wheeling you plan to do with your rig, you can dive right in to the best option for your needs. If you don't, it might be best to start small and slowly upgrade as you develop priorities and needs/wants. Going wheeling is the best way to understand what you like, and what you need to do it. It's almost always a safe bet to go with tires, skid plates and sliders as first mods, because you have a need for them almost regardless of what style of wheeling you do or what your goals are for your rig. As far as suspension - there are a few different ways to build your rig up, and what is ideal for someone might not be ideal for you based on how frequently you wheel (and how frequently you drive your rig on the street), your style of wheeling (rock crawling, overland, climbing hills, fire roads, etc.), and your budget. As John said, you'll get a ton of different opinions from everyone (and really, they're all right!), but the best thing is to do tons of reading/research and ask tons of questions to understand how each of these options will work for you, and what the pros/cons are of each. Only then can you make the most informed decision for yourself based on your goals and the way you plan to use your rig.