I'm in the UK. I'm also in a (parliamentary) seat which is pretty much a cert to be for a given party. It would be, even with AV. (As it happens, I also like the current incumbent, I've got no problem with him being our MP under any system, and he isn't a party-toady (nooffencetoourveryownToady!), but that's an aside.)
There's all kinds of talks about "wasted votes" under FPTP. But they aren't wasted. If you were to vote for the one-issue party with which you most relate then you count as support for it. It may not win, but it shows a significant amount of support. The problem is with people's voting techniques. They would go for OIP, but 'knowing' (believing, certainly) that they won't win they have a chance to reinforce the status-quo and vote for the incumbent or 'protest vote' by going for the usual major opposition.
People also tend to not vote for the candidate they like most, but vote for the party (usually in an "if they put a dead stoat up for conservative/labour/lib-dems/whoever's-the-usual-winning-party, they'd still win" situation) or even for a particular party leader!!! Or they protest vote against a particular party/leader. Either way, they might well be losing the opportunity to get the MP that they would have actually been able to 'use' more (either a moderate in a party that they don't like the extremism of, or a firebrand in a party that they think should be doing more.
None of that is an argument against AV, because you can do similar things (for better or worse) in AV. On the other hand, I'm a little concerned about the possibility that every candidate (who is seriously trying to win, at least) would, under AV, be not just trying to keep his own core supporters sweet but also try to 'spread bet' his promises so as to grab a few second-preference votes from other candidates' natural set of supporters. Especially the people whose first-preference votes are already pretty likely to be discarded because they're primary supporters of some fringe party. Thus Lab, Con and Lib (or at least whichever two of those three are the regular "first and second" in the area) candidates are all going "Yes, we like the [Health Service/Reduction Of Public Spending/Education* <delete as inapplicable>]" for their core voters but go on to say "and we're also going to be tough on immigration" to catch the BNP lot's interest, "cut down on pollution" to get the Green Party, and possibly even leach into the the "third party" mantra to catch some second preferences for when they get culled. Perhaps even copy their direct opposition in case they drop out. In other words, spread themselves thin. And then when it comes to fulfilling the promises, they won't be able to do it all. (Which probably means they won't be favoured so well next time the elections come around, which means that some other party that promises all and can't provide gets elected, and so it goes round.)
But, again, it all depends on how people react tot he opportunities, and vote. It'll take a few elections (two or three at a minimum, i.e. more than a decade, not including by-elections) for both parties and people to work out what they should be doing under the new system. And (as I've already said) some people don't know what to do with the current system, so they'd probably take far longer.
The 'advantage' to AV is that one can more easily see which direction people would like, though. "Labour controlled, with the second cumulative party to drop out being Green" should mean that people are more into environmental issues, which the Labour guy/gal needs to make sure they take note of. "Conservative controlled with second cumulative party being BNP" has its own message. (As would Lab/BMP and Con/Grn, in the previous examples, first part doesn't really matter.) "Liberal controlled with second party being Luke Skywalker Fanclub" might mean something.
The order by which the culls occur, together with how the votes redistribute, gives more of an idea about natural tendencies. And perhaps next time round people will be more inclined to 'waste' votes on a party that was more significant than they believed.
Note that I wrote the above two ways. One of them "FPTP is like <foo> but AV is like <bar>", which looked like I supported AV most, and the other being "AV is like <bar> but FPTP is like <foo>", which looked like I supported FPTP most. I've re-re-written it, and it worked most naturally in "currently, but if..." order but please don't try to read the natural preference into it.
Do you know what voting reform I'd really want, though? It can be done in FPTP and AV, and even full-on PR (which has its own problems, so I'd go for half-house by national PR, half-house by direct (double-sized) constituencies to avoid losing your own "point of contact" MP).
RON. Vote RON. "Re-Open Nominations". Currently, if you have a protest against the incumbent, or replacement for a retired/died incumbant, you can either vote for someone else (who you wouldn't normally vote for, but you reckon is a good signal to the 'ruling' party) which risks giving that party kudos you don't really think should be given, spoil your vote with a message of derision that will probably never make itself felt or not vote at all. Not voting at all could be (and often is, by those enjoying the low turnout of their competitors) interpreted as showing no confidence, but is likely as much composed of general apathy.
Imagine, though, that you really don't like one party, but you hate the rest. If you voted RON and RON came up trumps (but your party, your area generally being in agreement with you, at least comes in second) then that's a successful process. Under AV, you could vote RON, Your Party, ...other parties. Or even RON, Your Party and nobody else! You should even be able (assuming you had no issues with your party, which might be a minority, but you'd rather not support anybody else if you didn't have to) go for Your Party, RON and then all the others in some sequence or other, which says "This one please, but if not them I'd rather have nobody than the other lot". This would only work if Your Party was culled, but the second-choice RONs would build up when they did, if this was a common opinion.
The problem with RON is that if he wins (under whatever system), you need to run another election. Could be costly. But if it's what the people want... And if it sends a message, most people may de-RON (#...they do RON, RON, RON, they do RON, RON...#) their follow-up vote if they consider having have made the point.