Not sure if it's still made, it's been a while since I've messed with radio stuff, but the Alinco DX 70 is a decent unit for the price, HF plus 6 meters IIRC. Should be able to find one for less than $600.00
If its for HF work, the previous post is something to consider. The Kenwood TS-440 or TS-140 would be a nice choice. These radios were the latest in the late 80's, and in production into the 90's, now available in the 350 dollar range at a ham-fest. They are not back pack radios, but can run lower power to keep your battery happy, and still work all the bands. If you want a back pack radio this would be a lot to carry. if you want a dependable hard working radio these would be a choice worth considering.
A simple dipole antenna will work well if well designed and built. The ARRL publishes a handbook and an antenna book, both indispensable for an Amateur Radio Op. Everything in detail is shown and explained.
If you are looking for an expensive factory built antenna, I like the trapped verticals because of the multi-band capabilities. However someone once said, a vertical is omnidirectional and it will radiate poorly in all directions. Haha ! I have had good luck with my Hustler 6BTV vertical. It isn't the everything antenna, and as far as I know there is NO everything antenna, you will trade off cost, and performance, and nose factor, space, height, material, directability, and gain.
I would recommend you build a simple wire dipole antenna to get you going. There are quite a few decent wire antennas than you can modify your dipole to be once you are up and operating and get a bit of experience.
I used to have the entire setup years ago (Yaesu HF,UHF,VHF). After everything got stolen and no money to replace, I took this approach: With very little money (limited to overtime) I decided to just get a Yaesu hand held UHF,VHF about ($200.00) to hit the repeaters. I reasoned I could talk to hundreds of hams locally through the repeaters who in turn would have the HF base stations for coast to coast commo to relay info to me. I reasoned this is the best 1st step for me in getting back on the air for emergencies. As time permits and as I get the money. I can once again get the HF set up for the coast to coast commo.
P.S. you can get a 2 meter hand held for $100.00 or so but I wanted one that can also scan all police,fire and aviation freq which can be just as useful
Frequencies are downloadable at a lot of ham radio web sources, and the ARRL, these are the pictorial ham band charts handed out by the radio manufactures.
Another idea for a first HF radio, though not as instantly usable, is to build your own, from scratch if you have the skill or from a kit if you can follow instructions. If you don't have a portable SW radio, you can use that for starters as the receiver half. The SW radio will always be useful regardless if you move on to something different later on. If you learn the code, though no longer required, would allow you to build your own low power transmitter inside a "Altoids" mint sized container. Yes, that small. The great part is it will be tiny, shirt pocket portable. Note, if you are the least bit interested in code, pick a SW radio that has a BFO (beat frequency oscillator) so you can hear the CW (code) signals.
There was a post above about the Hustler series of vertical antennas, this may give you an idea how you might make a portable version if you want such a thing. Some years back I took a Hustler 4-BTV vertical antenna, and cut the sections to make the thing much more (truck camping) portable. I used color coded electrical tape to make the mating ends easily identifiable. Marking the exact lengths on the tubing as well to make set up faster. My wife made a carrying bag to package it neatly. I made a mounting bracket, 2 inch thin wall tubing welded into an "L" shape. The mounting bracket will slide into my trucks 2 inch hitch receiver. The nice part is I have a multi-band antenna that can be tossed in the truck and quickly set up. Dipoles are a must, but when you have the space to carry something like this is nice.