Any of the better name radios will be fine, just make sure it is 5W output, then choose the features that suit you. I have had GME in the past and am now using Uniden with all controls in the mic.
Which antennae to choose depends what you intend to do with the radio.
High gain antennas have longer range, but are less reliable in hilly conditions. Low gain ones give clearer reception for shorter range.
On the highway, there is no value listening to traffic 30 km away, better to hear those within 10km as clearly as possible, so we use those little rubber antennas that are about 200-300mm long and are zero to 1Dbi gain. They are cheap and almost unbreakable.
More important than gain is where the antennae is mounted. It should be as high as possible so there is no "shadow" from the vehicles. A bulbar mount is a long way from ideal.
Cheers,
Peter

Antenna gain roughly equates to signal reach. A low gain (typically around 3db) produces a spherical signal and has a corresponding reception space and is good on hilly, mountanous and dune country. A higher gain (typically 9db) has a "longer, flatter" transmission/reception space and is good in flat terrain. These are generalized comments and values, many other values exist. Most people compromise in the middle at 4.5 to 6db. Antenna mounting height is important but not critical, depends on your vehicle. Antenna construction, ie stainless, fibreglass determines durability on corrugations etc. Several manufacturers offer complete kits. I prefer OZ made GME, who sell "value packs". In the end, for close communication with nearby traffic on the road, any 5watt UHF will work.

Klaus, consider a roof rack mount antenna, if you have a rack. There is a fold down bracket for tight clearances, no wobbly bits in your vision and good/great reception as no vehicle obstacles. The controls all in the handpiece are also much better and the speaker there is much clearer. Mine is GME, but others are probably equal. The arial lead will probably sit at edge of windscreen with a few dabs of silicone, no flapping and a couple of good quality cable ties to rack.

Thank you iana 

For most UHF operators a glass (windscreen) mounted antenna coupled to a hands-free mounting kit is all that is necessary.

And the antenna will extend above the roof line of the vehicle to provide better reception.

I currently have a little Oricom which all the controls are on the mike which makes things easier. Bought it as a kit complete with aerial all in a box. Works very well. Range depends on terrain but have listened to road works ahead of us upto 20ks range but expect about 5 to 10ks on average for a 5watt unit. Oricom is an Australian company so I liked the idea of supporting a local mob.