I work as a guide/translator/assistant for guys who travel to Ukraine and my thoughts are as follows:
I have never personally hired a guide when i have travelled. The reason is that i like to make my travelling as adventurous as possible, normally I am not restricted to a small time frame, and I am particularly adept at getting round in unfamiliar circumstances.
Ive seen guys come here with and without guides. Theres an argument each way but for many guys who havent travelled much, have only a short time in the country, and want to get results, a guide works well. This can be for just part of their stay, for a few hours each day, or a full-time assistant. A lot depends on the individuals character and expectations.
The way i see it is that although i am personally an expense, i save my client money in every other way possible...and in Ukraine the main problem is that unsuspecting foreigners can be subject to being incessantly ripped-off (more often than not by marriage agencies!), taxis, restaurants, accommodation owners, the girls...theyre all at it! and i get job satisfaction from getting my client the best deal every time.
In this way a guide can be a good thing. For sure though..for the extra adventurous types (particularly those who thrive on the adventure) then there are particular advantages of going it alone.
Happily everyone can make their own choice!

1) Airport Transfers
I would ask the apartment service to arrange transfers and I know some do it for free. I know my girl offered to pick me up from the airport but I preferred to arrive before her and pick her up from the train station. I think newbies can be made aware what an appropriate fare is from the airport to the city and then surely they can barter a decent price themselves?
2) Apartments
There's SO MANY apartment services on the web as far as I'm concerned anyone will do! The one in the links here at RWD has a terrific range of apartments available.
3) Sightseeing
I wouldn't pay a guide for sightseeing because it would take the adventure out of the trip. There are guidebooks available on the street in Kiev's city centre and I would imagine they are available in most other large cities.
I'd love to see us (the members of RWD start to document "things to see and do" in the cities we're familiar with so others can explore new and interesting places.
4) Night time outtings to pubs, clubs or restaurants
I don't believe it's "so dangerous" unless you're foolish! Again, tips from RWD members would be a great help!
5) Booking Bus, Train and Airline tickets
Air tickets are dead easy! Do them online. Bus and train tickets can be bought (for a very small fee) through registered tour agencies.
6) Cold introductions to girls on the street (as someone suggested)
I think the suggestion was a joke.. SURELY!!! I can't imagine any girl being interested in an English speaking guy on the street if she didn't speak English and had to use a guide to get her attention. Forget it.. it's not going to happen!
7) Translations with girls you've been writing to prior to arrival
Goodness gracious... You've been corresponding with a girl and you arrive for a visit and she doesn't speak any English? If you found her online in a messaging program surely she speaks some English. If you need assistance I reckon an electronic translation tool sounds like a workable solution... or this MAY be a rare occasion a guide can be of service.
If you're using a guide for this I would confirm the price per hour prior to arriving in the city and ensure the guide knows where to meet you and for how long. Don't get the guide to pick you up and hold your hand on the way to the cafe, it's a waste of money!
Translations with girls you meet through agencies
Use the agencies. I've heard some suggestions you can't trust the agencies but if you can't trust them for translations you shouldn't be trusting them for introductions. ONLY USE REPUTABLE AGENCIES!
9) Meet the guides friends in the hope of finding a girl
If a guide offers you an introduction to his or her friends treat it as an inducement. Plan ahead and make sure your Plan B comes with lots of options rather than a last minute grab for "success".
10) Taking you to the hospital if you get sick
Travel Insurance??? I know it's obvious but if you have travel insurance you're covered for this!
11) Dealing with police if you get in trouble
Kinda a light hearted question to lighten the discussion. If you're in trouble with police you probably deserve it. I met a guy in O'Briens who was complaining the police jumped out from the shadows while he was walking home the night before. he reckons he was minding his own business but when another guy turned up that he was with from the night before the full story came out. he'd picked up a hooker and got out of the taxi a block from his apartment. As they were walking to the apartment they were stopped by police and had to pay 100UAH to pass. Serves the dirty sex tourist right in my mind!
12) Arranging prostitutes (if you're a sex tourist)
Do this and you're a fool! What are you going to FSU for? Sex or marriage. If you're going for sex you you deserve everything you get!
13) Arranging a mobile phone and Internet
Walk into a shop! They are peppered thoughout the cities I visited and I was able to buy a SIM card without a problem. You don't need a translator for this!
14) Judging the quality of your girl (as someone suggested)
Someone told me a guide was a good person to tell you what your girl is really like... They must have been kidding right? If you can't work that out for yourself you shouldn't be in FSU!
15) Giving advice on the cheapest method of getting to other cities
The best advice you'll get on travelling within FSU is here... RWD! Guides may not give you the best advice!
16) Arranging a private car to get around the city
Stick your hand ot when standing on the side of the street. Again if we at RWD could give an indication of Taxi or Private car costs newbies travelling to new cities will at least be armed with credible information!
17) Dealing with Agencies for you
Choose a credible agency based on the recommendations in RWD and stick to ONLY those agencies. You don't need a guide to do this for you!
18) Visas (if you need them)
Use an AUTHORISED Tourist operator or if you're staying in a hotel at some time during your stay get the Visa Invitation from them. Guides (apparently) will only give you a personal invitation and that needs to be stamped and send in original format to you for submission with your Visa application. An Authorised Tourist operator can give you an electronic document. Faster... and cheaper!
19) Helping with groceries and shopping?
Oh so easy to do yourself!